Calguns.net  

Home My iTrader Join the NRA Donate to CGSSA Sponsors CGN Google Search
CA Semiauto Ban(AW)ID Flowchart CA Handgun Ban ID Flowchart CA Shotgun Ban ID Flowchart
Go Back   Calguns.net > GENERAL DISCUSSION > General gun discussions
Register FAQ Members List Calendar Mark Forums Read

General gun discussions This is a place to lounge and discuss firearm related topics with other forum members.

Reply
 
Thread Tools Display Modes
  #1  
Old 12-01-2016, 11:16 PM
repoman1984's Avatar
repoman1984 repoman1984 is offline
Senior Member
 
Join Date: Jun 2009
Location: LA, 43 in DMZ
Posts: 1,051
iTrader: 15 / 100%
Default The science of controlling chamber pressure in semi auto actions?

Anyone else thought about this? There are over a dozen methods of semi-auto actions, strait blow-back, browning tilting barrel, roller delayed, flapper lock, gas piston, gas direct impingement etc etc etc.

Now what really cooks my brain is you have the HK mp5, with its really elaborate roller locking action then... some new companies make copies or "clones" of mp5 type carbines/rifles and they don't even bother with roller locking actions, just a spring and bolt/bolt carrier strait blowback. huh? It almost proves that the rollers were never required for that cartridge to function at all in that type of firearm. Once more there are even modern manufactured 5.7x28 strait blowback actions the 5.7 runs at 50,000psi WAY hotter than half the combat pistol rounds . This really seems half science and half marketing. Is there a scientific formula for PSI/time/resistance, modern firearms are built around?
__________________
Sapper Morton: How does it feel? Killing your own kind?

K: I don't "retire" my own kind, because we don't run...
Reply With Quote
  #2  
Old 12-02-2016, 7:04 AM
Socalmp5 Socalmp5 is offline
Senior Member
 
Join Date: Jan 2012
Posts: 685
iTrader: 7 / 100%
Default

The Hk series of fire arms were designed to run full auto. The different locking pieces controlled the different pressures from different types of ammo. I can almost guarantee that straight blowback in full auto isn't as controllable and reliable.
Reply With Quote
  #3  
Old 12-02-2016, 9:58 AM
repoman1984's Avatar
repoman1984 repoman1984 is offline
Senior Member
 
Join Date: Jun 2009
Location: LA, 43 in DMZ
Posts: 1,051
iTrader: 15 / 100%
Default

So you are saying a roller lock would reliably run far more different loads or it was "adjustable" to fit a ideal load that would be repeatedly used?
__________________
Sapper Morton: How does it feel? Killing your own kind?

K: I don't "retire" my own kind, because we don't run...
Reply With Quote
  #4  
Old 12-02-2016, 10:19 AM
ojisan's Avatar
ojisan ojisan is offline
Agent 86
CGN Contributor
 
Join Date: Apr 2008
Location: SFV
Posts: 11,689
iTrader: 59 / 100%
Default

Ehhh...roller lock is really only needed for rifle pressure cartridges.
There are plenty of semi and full auto 9mm subguns that run reliably using the simple blowback action.

Now a blowback does require ammo that will generate the proper pressures to operate it.
However, almost all 9mm ammo is suitable as that is what the guns were designed to run.
__________________

Quote:
Originally Posted by Citadelgrad87 View Post
I don't really care, I just like to argue.
Reply With Quote
  #5  
Old 12-02-2016, 10:27 AM
cvigue cvigue is offline
Senior Member
 
Join Date: Jan 2015
Posts: 1,525
iTrader: 1 / 100%
Default

A properly operating straight blowback design uses the reciprocating mass and spring to hold the action closed (enough) to operate correctly. One advantage of a locking system is that it can be engineered lighter and still operate properly.
Reply With Quote
  #6  
Old 12-02-2016, 10:40 AM
elSquid's Avatar
elSquid elSquid is offline
In Memoriam
 
Join Date: Aug 2007
Location: Left coast.
Posts: 11,844
iTrader: 6 / 100%
Default

One of the oft discussed advantages of the MP5 was the closed bolt operation, which meant that the trigger released a hammer vs the typical open bolt SMG which had this huge chunk of metal - the bolt - that slammed forward after the trigger was pressed.

Were there any closed bolt, striker fired, blowback SMGs that saw military issue?

-- Michael
Reply With Quote
  #7  
Old 12-02-2016, 10:49 AM
hermosabeach's Avatar
hermosabeach hermosabeach is offline
I need a LIFE!!
 
Join Date: Feb 2009
Location: South Bay of Los Angeles
Posts: 18,384
iTrader: 12 / 100%
Default

Roller locker in the rifle has some weird characteristics.

The lines on the brass as the gas shot past the brass due to flutes in the barrel

The roller locker worked well in the CZ52 and the MP5


Firing a machine gun, the chamber got hot and would cook off a live round...

So machine guns fired from open bolt position

This allowed the ammo to stay in the feeding device- mag or belt and the action to stay open... air could faster cool the barrel / chamber and the round would not be cooked by being in contact with the chamber.


But open bolt is not as accurate as closed bolt



Closed bolt then had fluted chambers to reduce the surface area of the hot chamber with the loaded round....


So what are you trying to accomplish???
Each action type has advantages and drawbacks....
__________________
Rule 1- ALL GUNS ARE ALWAYS LOADED

Rule 2 -NEVER LET THE MUZZLE COVER ANYTHING YOU ARE NOT PREPARED TO DESTROY (including your hands and legs)

Rule 3 -KEEP YOUR FINGER OFF THE TRIGGER UNTIL YOUR SIGHTS ARE ON THE TARGET

Rule 4 -BE SURE OF YOUR TARGET AND WHAT IS BEYOND IT
(thanks to Jeff Cooper)
Reply With Quote
  #8  
Old 12-02-2016, 12:48 PM
Socalmp5 Socalmp5 is offline
Senior Member
 
Join Date: Jan 2012
Posts: 685
iTrader: 7 / 100%
Default

Quote:
Originally Posted by repoman1984 View Post
So you are saying a roller lock would reliably run far more different loads or it was "adjustable" to fit a ideal load that would be repeatedly used?
Yes... There are a few different locking pieces for the .308 G3 series of rifles, more so then mp5..

It was easier for Hk to scale down for the 9mm then make a whole new animal... Keep in mind the mp5 was designed in the 60s.
Reply With Quote
  #9  
Old 12-02-2016, 3:34 PM
repoman1984's Avatar
repoman1984 repoman1984 is offline
Senior Member
 
Join Date: Jun 2009
Location: LA, 43 in DMZ
Posts: 1,051
iTrader: 15 / 100%
Default

Interesting stuff, I've been contemplating building a California compliant MP5 type pistol or carbine for a while now. Will an HK style roller locked 9mm damage brass beyond reloading?
__________________
Sapper Morton: How does it feel? Killing your own kind?

K: I don't "retire" my own kind, because we don't run...
Reply With Quote
  #10  
Old 12-02-2016, 10:39 PM
sbo80's Avatar
sbo80 sbo80 is offline
Senior Member
 
Join Date: Apr 2014
Location: San Diego
Posts: 2,224
iTrader: 25 / 100%
Default

I never looked closely at the brass, but I have fired several MP5's on full-auto, and the ejection of the brass didn't seem unusual compared to a handgun. I know that doesn't answer anything about chamber behavior, but that there doesn't seem to be extra force/velocity given to the bolt/ejector that passes on to the brass. The G36 on the other hand, sends brass flying really far, and lots of those casings (5.56) had dented sidewalls from hitting the deflector.
Reply With Quote
  #11  
Old 12-03-2016, 5:06 AM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
Originally Posted by repoman1984 View Post
Anyone else thought about this? There are over a dozen methods of semi-auto actions, strait blow-back, browning tilting barrel, roller delayed, flapper lock, gas piston, gas direct impingement etc etc etc.

Is there a scientific formula for PSI/time/resistance, modern firearms are built around?
There is nothing so simple as a "formula", but all the stresses, strains, and action dynamics are based on the Newtonian laws of motion. Semi automatic actions are carefully refined around engineering principles and material allowances. The roller bolt actions are amazing, in my opinion.

But, the best place to start is with Chinn's Machine Gun series. Go to Vol IV and read the section on blowback.

All the books are downloadable but Vol IV is the principles of the things and therefore, the most value added:

http://www.ibiblio.org/hyperwar/USN/ref/MG/

http://www.ibiblio.org/hyperwar/USN/ref/MG/IV/MG-V4.pdf

Once you read the blowback section you will have a very good idea of pressure and dwell which are foundational for understanding semi automatic mechanisms.

I don't know why Chinn does not have the fluted chamber in his series, the books were written in the early 50's and the diffusion of knowledge of the roller action and fluted chamber must not been reached these shores yet.

Prior to the fluted chamber all high power blowbacks or delayed blowbacks lubricated the cases with variations of oil, grease, or waxes.



The Schwarzlose machine gun has an oil tank on top:



So does this Breda M30 Italian machine gun



As well as this Japanese Nambu





Pedersen used a wax coating for his delayed blowback




All of these systems of cartridge lubrication basically went on the ash heap of history after the fluted chamber. From what I have read, the Germans captured a Russian machine gun, which had a fluted chamber, and the rest is history. Flutes eliminated the oiler mechanism and the oil can that the trooper had to carry. Chamber flutes break the friction between the upper 2/3's of the case and chamber.




All of this history confounds Hatcherism, but nothing confounds Hatcherites. The knowledge of oiled cartridges, greased cartridges has been mostly forgotten by the American shooting community, instead Hatcherites believe that oiled, greased, lubricated cartridges are dangerous, they "dangerously" raise pressures, over load the bolt mechanism, etc, etc, etc. Of course this is non sense, Hatcherism derives from a century old Army coverup of their defectively built single heat treat 03's and overpressure ammunition the Army issued in 1921. Fluted chambers have been so successful that the memory of oilers and greased cartridges have been quite forgotten in the American shooting community.

Breaking the friction between the case and chamber is in fact, desirable for a number of reasons. This first is that function reliability is improved for all semi automatic mechanisms as the case is easily extracted. Fluted chambers are even making their appearance for non roller bolt actions, such as XTRAXN rifles, which are based on the AR15. XTRAXN fluted their chambers and I think this is a great idea. Other than cost, I think all semi auto or full auto chamber should be fluted as breaking the friction between case and chamber will always improve extraction reliability.





Reply With Quote
  #12  
Old 12-03-2016, 7:35 AM
MrOrange's Avatar
MrOrange MrOrange is offline
Senior Member
 
Join Date: Aug 2006
Location: The Second Place Metal State
Posts: 2,262
iTrader: 33 / 100%
Default

Quote:
Originally Posted by cvigue View Post
A properly operating straight blowback design uses the reciprocating mass and spring to hold the action closed (enough) to operate correctly. One advantage of a locking system is that it can be engineered lighter and still operate properly.
That's about it. The HK system is just a delayed blow-back, and repoman1984 you are correct in supposing "that the rollers were never required for that cartridge to function at all in that type of firearm."

There have been anti-aircraft guns that were straight blowback actions. Another blowback you might've heard of is the Mk 19 grenade launcher.
__________________
I meant, it is my opinion that...






I do believe that where there is a choice only between cowardice and violence
I would advise violence. - M. Gandhi
You're my kind of stupid. - M. Reynolds
Reply With Quote
  #13  
Old 12-04-2016, 1:42 PM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
There have been anti-aircraft guns that were straight blowback actions.

The US Army adopted the Oerlikon 20 mm machine cannon prior to WW2. This 20 mm machine cannon was used on basically, everything. It was the 20mm cannon used on bombers and fighter aircraft, used on ground emplacements, used on capital ships, and also used on PT boats.




The Germans, and I believe the Japanese used versions of the Oerlikon. Col Chinn has chapters on the various versions of the Oerlikon, the US Army Ordnance Department made about 150,000 of the things, and according to Chinn, the Oerlikon and its Navy versions were produced in more quantity than any other machine cannon. The Oerlikon was used up to Vietnam.

It was an advanced primer ignition blowback. This is from Chinn's series:




This mechanism could not function unless the cartridges were heavily greased.



I found Navy documents, such as NRL Memorandum Report 562 A LABORATORY INVESTIGATION OF CARTRIDGE LUBRICANTS FOR 20MM F.A.T.-16 STEEL CARTRIDGES where after WW2 investigations into oilers, greased cartridges, waxed cartridges, and Teflon coated cartridges in an attempt to make the Oerlikon function with steel cases.

What I find amazing is that Major General Hatcher, who was the Head of Army Ordnance during WW2, after making 150,000 Oerlikon's, and he was given a copy of Chinn's Machine Gun series to review before printing, and yet MG Hatcher writes a long and detailed section in his book "Hatcher's Notebook" claiming that greased and oiled cartridges dangerously raise combustion pressures and bolt thrust!

I don't know if any civilians ever owned an Oerlikon 20mm machine cannon, the things fired rounds around 700 to 800 rpm, and considering the cost of 20mm shells, the cost of firing one must be on the order of $1,000 to $2,000 a minute. Plus, while the cannon was around 100 lbs, the pedestal and deck mounts are much heavier, so this is not something you can carry in your backpack. For these reasons, and probably many others, the civilian shooting community has basically forgotten these mechanisms and how they operated.

As for the MP-5, I don't have one and I don't know whether the thing is a direct blowback or a retarded blowback or not. Whether the roller lugs actually provide any resistance would be a matter of inertia. If the bolt is heavy enough, than inertia alone would suffice in delaying bolt opening to allow breech pressure to decrease enough that the cartridge sidewalls don't rupture. If however, the MP-5 has a lighter bolt, than it is very possible that HK engineered the thing so the roller lugs actually perform the function of a semi rigid locking mechanism. A lighter bolt is an advantage. I had the good luck to fire a Swedish 9mm blowback machine gun, and it rocked and rolled due to the heavy bolt. A lighter bolt would allow better shot placement on full automatic. I do know the MP-5 has a fluted chamber, and regardless of whether the roller lugs provide any resistance to opening, I think chamber flutes are a great idea and improves extraction.

Quote:
Once more there are even modern manufactured 5.7x28 strait blowback actions the 5.7 runs at 50,000psi WAY hotter than half the combat pistol rounds
This cartridge is also lubricated with a "polymer substance". The manufacturer's of the round don't want to tell the American public the round is lubricated, or that the lubricant is a grease, oil, or wax (or maybe Teflon) because the American public has been trained to react hysterically to cartridge lubrication, and will do so. So they call the coating a "polymer". But greases, oils, waxes, and Telfon, are all polymers and regardless of the hysteria in the American shooting community against cartridge lubricants, the cartridge is coated with a lubricant. And, based on web reports, if you resize the cartridge case and do not restore the lubricant layer, the cartridge case will rupture, and that has caused injuries to reloaders.

It is just as Chinn said, high power blowbacks ought to be called "oil-o matics."

Last edited by slamfire1; 12-04-2016 at 1:44 PM..
Reply With Quote
  #14  
Old 12-04-2016, 8:09 PM
saki302's Avatar
saki302 saki302 is offline
Calguns Addict
 
Join Date: Oct 2005
Location: Los Angeles, CA
Posts: 7,134
iTrader: 94 / 100%
Default

The roller lock adds enough delay and reduction in force to allow a weaker recoil spring or less bolt mass.

Try cocking the bolt on a semi Sten or Thompson- you almost need two hands or to weigh over 200lbs
The other option is to add weight to the bolt group. That's why blowback Hi-points have such heavy slides.

-Dave

PS- the 5.7 has a coating to allow it to work in the P90. The coating lubes the weird 90 degree turn in the mag. If you tumble it off, it'll still work in the 5.7 pistol, but not reliably in the carbine.
Reply With Quote
  #15  
Old 12-04-2016, 8:53 PM
NorCalAthlete's Avatar
NorCalAthlete NorCalAthlete is offline
Senior Member
 
Join Date: Jul 2010
Location: San Mateo
Posts: 1,796
iTrader: 19 / 100%
Default

Quote:
Originally Posted by repoman1984 View Post
Interesting stuff, I've been contemplating building a California compliant MP5 type pistol or carbine for a while now. Will an HK style roller locked 9mm damage brass beyond reloading?
Keep us posted on what you end up with! I've been hunting around for something MP5-like in 9mm for a fun range toy. Debated on the 9mm AR but kinda want something different.
__________________
Your views on any given subject are the sum of the media that you take in, scaled to the weight of the credibility of the source that provides it, seen through a lens of your own values, goals, and achievements.

You Are All Ambassadors, Whether You Like It Or Not

Pain is the hardest lesson to forget; Ego is the anesthesia that deadens the pain of stupidity.

Bureaucracy is the epoxy that lubricates the gears of progress.
Reply With Quote
  #16  
Old 12-05-2016, 6:54 AM
MrOrange's Avatar
MrOrange MrOrange is offline
Senior Member
 
Join Date: Aug 2006
Location: The Second Place Metal State
Posts: 2,262
iTrader: 33 / 100%
Default

Quote:
Originally Posted by slamfire1 View Post
(snipped)
The US Army adopted the Oerlikon 20 mm machine cannon prior to WW2. This 20 mm machine cannon was used on basically, everything. It was the 20mm cannon used on bombers and fighter aircraft, used on ground emplacements, used on capital ships, and also used on PT boats.

The Germans, and I believe the Japanese used versions of the Oerlikon. Col Chinn has chapters on the various versions of the Oerlikon, the US Army Ordnance Department made about 150,000 of the things, and according to Chinn, the Oerlikon and its Navy versions were produced in more quantity than any other machine cannon. The Oerlikon was used up to Vietnam.

It was an advanced primer ignition blowback.
I stand corrected. I was thinking the earliest versions the US used were straight blowback, based on a WWII vet referring to them as such. He wrote that even though they were well secured on heavy mounts, it took a strong man to rack the action. According to Wiki, Oerlikon API guns are still in use today around the world.

Chamber flutes seem like a good idea in general. Most gun folk know that a main weakness of the AR design is weak extraction, and to help out P.O.F. incorporates flutes in the neck area of their "E2" chambers. Might've helped in this example, as it looks like the BCM extractor spring upgrade did all it could and came up short:



This happened to me on the first round of a new build; don't know what caused the FTE but every round after that was gravy.
__________________
I meant, it is my opinion that...






I do believe that where there is a choice only between cowardice and violence
I would advise violence. - M. Gandhi
You're my kind of stupid. - M. Reynolds
Reply With Quote
  #17  
Old 12-05-2016, 9:13 AM
ojisan's Avatar
ojisan ojisan is offline
Agent 86
CGN Contributor
 
Join Date: Apr 2008
Location: SFV
Posts: 11,689
iTrader: 59 / 100%
Default

Breda, Schwarzlose, Nambu and many other early MGs all fought the problem of too-early breech opening.
Too-early opening resulted in the bolt trying to pull the case out of the chamber while the case was still expanded and stuck to the cylinder walls.
Same as an over-gassed AR.
This caused failure to extract, broken extractors or case heads / rims being ripped off.
Lubricated cartridge cases helped with the extraction problem, but lead to a new problem with the sticky lubed cases attracting dirt and mud that fouled or jammed actions.
This is a reason why lubed cases went away, and are so disliked.
Fluted chambers were used to reduce the case-to-chamber-wall contact area so the fired cases were easier to extract.

Long or short recoil designs kept the breech closed longer so the extraction problem wasn't an issue. (JMB designs).
__________________

Quote:
Originally Posted by Citadelgrad87 View Post
I don't really care, I just like to argue.
Reply With Quote
  #18  
Old 12-05-2016, 10:19 AM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
I stand corrected. I was thinking the earliest versions the US used were straight blowback, based on a WWII vet referring to them as such. He wrote that even though they were well secured on heavy mounts, it took a strong man to rack the action. According to Wiki, Oerlikon API guns are still in use today around the world.

I originally thought the Oerlikon was a retarded blowback. It took a re reading to understand that it was an advanced primer ignition. Considering all the recoil a 20mm round puts out, the breech block for a simple blowback 20mm cannon would be huge and so would be the recoil! I understand the advanced primer ignition mechanism had its own issues. One can imagine what would happen with a hangfire. The advanced primer ignition feature relies on the forward moving inertia of the breechblock for its timing. If the block is not moving forward, but instead at rest, when the round goes off, the case would be extracted under high pressure and the case walls would rupture once the case head clears the chamber. Kaboom!

This is a fun video, you can see at exactly 2:14 on this WW2 video a Sailor’s hand painting grease on the 20 mm ammunition loading machine for the Oerlikon anti aircraft machine guns.

http://www.youtube.com/watch_popup?v=9dR3h2HdnBQ


There is a very interesting WW2 document, Ordnance Pamphlet 911, at this web site.

http://archive.hnsa.org/doc/gun20mm/index.htm

You can see the Navy version and its pedestal and deck mount on the second page, and the instructions for lubricating the rounds on this page:

http://archive.hnsa.org/doc/gun20mm/part4.htm#pg105


I regularly rail against the phobias and schizophrenic understanding of the laws of physics that the general shooting community has about case lubrication and lubricated cases. At one level, you won't get a reaction about chamber flutes, which provide gas lubrication, but once greases, oils, or waxes are mentioned, you get a hysterical response about the dangers of lubricated cases and lectures about the dangerous of increasing bolt load by lubing cases. Newtonian physics are very consistent (small modifications around massive gravitational bodies) and since we are not shooting black holes in our rifles, load in foot pounds is load in foot pounds.

And there are all these examples of mechanisms that used greased and oiled ammunition, and, we have these mechanisms using flutes to break the friction between case and chamber. So it is very frustrating that the general shooting public still adheres to an century old Army coverup that lubed cases are dangerous.

I regularly lube my cases on first firing, so I don't get case head separations as the case fills the chamber, and I have been lubing my cases for Garands and M1a's for decades now, because the case basically last forever.
Reply With Quote
  #19  
Old 12-05-2016, 11:00 AM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
Breda, Schwarzlose, Nambu and many other early MGs all fought the problem of too-early breech opening.

Too-early opening resulted in the bolt trying to pull the case out of the chamber while the case was still expanded and stuck to the cylinder walls.
It is not as if these mechanisms were failures. Yes, unlock occurred early, and that required case lubrication, but the mechanisms were highly reliable and were used world wide in combat conditions. There were a lot of fielded retarded blowback mechanisms and I believe there are a couple of reasons why. The first is that parts could be eliminated. No operating rod, gas cylinder, etc. Another reason is that the cyclic rate could be increased. The time it takes to unlock, either a titling block, rotating bolt, etc, that time period could be eliminated. I don’t think it any coincidence that the advanced primer ignition Oerlikon was an extremely fast mechanism. After WW2 the need for a faster firing machine cannon came about because jet airplanes were going so fast. Even the single barrel Oerlikon was not fast enough, so multiple barrel guns, like the Vulcan were adopted.

Hatcher explained, in Army Ordnance Magazine, March-April 1933, how cases stretch and why lubrication is essential in retarded blow back mechanisms:


Automatic Firearms, Mechanical Principles used in the various types, by J. S. Hatcher. Chief Smalls Arms Division Washington DC.

Retarded Blow-back Mechanism………………………..

Quote:
There is one queer thing, however, that is common to almost all blow-back and retarded blow-back guns, and that is that there is a tendency to rupture the cartridges unless they are lubricated. This is because the moment the explosion occurs the thin front end of the cartridge case swells up from the internal pressure and tightly grips the walls of the chamber. Cartridge cases are made with a strong solid brass head a thick wall near the rear end, but the wall tapers in thickness until the front end is quiet thin so that it will expand under pressure of the explosion and seal the chamber against the escape of gas to the rear. When the gun is fired the thin front section expands as intended and tightly grips the walls of the chamber, while the thick rear portion does not expand enough to produce serious friction. The same pressure that operates to expand the walls of the case laterally, also pushes back with the force of fifty thousand pounds to the square inch on the head of the cartridge, and the whole cartridge being made of elastic brass stretches to the rear and , in effect, give the breech block a sharp blow with starts it backward. The front end of the cartridge being tightly held by the friction against the walls of the chamber, and the rear end being free to move back in this manner under the internal pressure, either one of two things will happen. In the first case, the breech block and the head of the cartridge may continue to move back, tearing the cartridge in two and leaving the front end tightly stuck in the chamber; or, if the breech block is sufficiently retarded so that it does not allow a very violent backward motion, the result may simply be that the breech block moves back a short distance and the jerk of the extractor on the cartridge case stops it, and the gun will not operate.

However this difficultly can be overcome entirely by lubricating the cartridges in some way. In the Schwarzlose machine gun there is a little pump installed in the mechanism which squirts a single drop of oil into the chamber each time the breech block goes back. In the Thompson Auto-rifle there are oil-soaked pads in the magazine which contains the cartridges. In the Pedersen semiautomatic rifle the lubrication is taken care of by coating the cartridges with a light film of wax.

Blish Principle….There is no doubt that this mechanism can be made to operate as described, provided the cartridge are lubricated, …. That this type of mechanism actually opens while there is still considerable pressure in the cartridge case is evident from the fact that the gun does not operate satisfactorily unless the cartridges are lubricated.
By the way, this is the same J. Hatcher who told the world that greased and oiled cartridges were dangerous, in his 1948 book, Hatcher’s Notebook. To me, it shows how even an intelligent man will accept contradictory, if not schizophrenic concepts, in order to conform to the norms of his organization.

Quote:
Same as an over-gassed AR. This caused failure to extract, broken extractors or case heads / rims being ripped off.

I am certain that an overpressure round, or a mechanical issue, where the timing was off, a delayed blowback would have equal problems, but it does not make the mechanism a failure. In fact, without flutes, the HK91 would rip cases in half, or rip rims off. The fluted chamber allowed that gun to function, and it has been adopted as a service arm and been successfully used world wide.

Quote:
Lubricated cartridge cases helped with the extraction problem, but lead to a new problem with the sticky lubed cases attracting dirt and mud that fouled or jammed actions.
This is a reason why lubed cases went away, and are so disliked.
Oiled and greasy cases are a mess and they do attract dirt. Dirt is very abrasive and will scratch and scar chambers and barrels. This is the primary reason a Council of Colonels told Major Whelen to write up a pamphlets, in 1921, about the evils of grease, and get greased bullets out rifle shooting. Major Whelen had oversold his tin coating on bullets, he had everyone convinced that he had found the solution to bullet jacket fouling. Major Whelen so convinced himself that he absolutely ignored evidence that his tin coating caused a bore obstruction. The problem of eliminating jacket fouling was a major problem at the time and the solution would be a major milestone for centerfire rifle shooting. While Major Whelen would not have received a Noble prize for this, the career boost would have been huge. As it turned out, his minions at Frankford Arsenal produce a fallacious study, to keep their Boss happy, and that study is what Hatcher quotes in his book. This information was published in the Arms and the Man prior to the National Matches and it happened to save Major Whelen’s bacon, at least in the short run. Once his tin can ammunition got to the National Matches it blew up rifles, but the Army Ordnance Bureau had Major Whelen’s study which “proved” there was nothing wrong with the ammunition or the rifles, it was all due to the grease. This is what the Army said at the time:

1 Oct 1921 Arms and the Man, Editorial by Brig-Gen Fred H. Phillips, Jr, Secretary NRA
The National Match Ammunition

Quote:
Use of the national Match ammunition through the Camp Perry shooting season has amply demonstrated that, in the hands of intelligent rifleman, the “tin can” cartridge may be regarded as absolutely safe.

The fact that the National Matches closed without recording one serious accident in connection with the use of this ammunition seems to be a final and clinching argument, that when properly handled, no disastrous results may be expect. The only instance of rifles having been damaged-there were two out of the thousand-odd in use that suffered from “blow back”-were cause the presence of grease in excessive quantity and were the result of the shooter’s own carelessness. Fortunately the men who experience the blow backs were only superficially hurt. The lesion, however, in connection with the blow backs was plain.

The high degree of accuracy attained in the manufacture of this ammunition cannot be question. It is without a doubt the finest machine-made product that has ever been turned out.

The high quality of this ammunition, together with the remarkable accuracy properties of the new type of National Match rifle will do a very great deal toward promoting the art of marksmanship. ….
.
Whether the new “tin can” type ammunition may be regarded as a suitable service load for use by troops in the field is a matter for later an more mature determination. But little more could be expected in accuracy and wind bucking qualities from a strictly machine-made product than that exhibited by this year’s tin-plated ball cartridges.
This is in fact, a lie. This is an Army coverup, the tin can ammunition was dangerous, the tin bullet cold soldered to the case neck and caused a bore obstruction and blew up rifles. The blow up had nothing to do with grease or oil, but that is not the version of history that the general shooting public accepts.

I am very surprised the Townsend Whelen made Col. He had the resources of an Arsenal, and yet his management style prevented his team from surfacing the problems of tin coated bullets. He knew of the problem and so must his minions, but, even so, they produced millions of dollars of expensive ammunition that was so dangerous, whatever remainder existed after the National Matches had to be scrapped.

Sort of reminds me of Hillary Clinton. Even though she was in charge of the State Department, her "team" failed to keep her from sending tens of thousands of classified emails over an insecure system. That showed the lady was not fit for command, and thankfully, she did not get promoted.

Last edited by slamfire1; 12-05-2016 at 11:04 AM..
Reply With Quote
  #20  
Old 12-05-2016, 11:13 AM
ojisan's Avatar
ojisan ojisan is offline
Agent 86
CGN Contributor
 
Join Date: Apr 2008
Location: SFV
Posts: 11,689
iTrader: 59 / 100%
Default

Actually I have not read either Hatcher or Whelen on these topics.
Interesting info for sure.
During WW1, many lubed case designs were relegated to stationary / fortress use where the environment was much cleaner than in the muddy trenches.
The Japanese in WW2 had plenty of trouble with lubed cases and sandy pacific island environments.

I find the different early auto loading breech designs to be a fascinating study.
So much experimentation, and the ingenuity of the various solutions as problems appeared.
__________________

Quote:
Originally Posted by Citadelgrad87 View Post
I don't really care, I just like to argue.
Reply With Quote
  #21  
Old 12-05-2016, 12:06 PM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
During WW1, many lubed case designs were relegated to stationary / fortress use where the environment was much cleaner than in the muddy trenches.

Mauser came up with the first issue semi auto matic rifle: the Selbstlader-Karabiner Mauser M 1916 http://www.forgottenweapons.com/earl...r-selbstlader/ and it used greased 8 X 57 mm cartridges! And, it was so dirt sensitive it was issued to the Zeppelin service.


Quote:
The Japanese in WW2 had plenty of trouble with lubed cases and sandy pacific island environments.
I have been out the South Pacific and the little islands I was on, things rusted overnight. Temperatures were 90 degrees and the humidity was 80% at night! The air was so thick with humidity it was like being in a steam bath. A bicycle would rust to unusable condition in a week. I am certain US weapons had their own issues in that environment. All semi automatic weapons have issues in sandy desert environments. I have talked to a number of Veterans of Iraqi, and those in the sandy South were having to clean their M4's/M16's three times a day.

Quote:
Actually I have not read either Hatcher or Whelen on these topics.
Good for you! There are forums, such as Culver's, where Hatcher and Whelen are worshiped as Demigods and their words are inviolate. Make statements on that website that they were part of a coverup, posters there will produce replies such as this:

Quote:
I would simply remind you that MG Hatcher was directly involved in small arms programs and ammunition developments throughout the 1903 era, and beyond.

He eventually rose to be Chief of Field Ordnance, in WW2.

He was not given to guesswork or repetition of rumor.

All of his statements on the topic of grease and the tin-can ammunition problem were based on direct observation and instrumented tests, using all the resources available to Ordnance at the time.
That was one of the nicer posts, others can be nasty and cruel, but then, what do you expect from people who ignore evidence in the physical world that their Holy Texts are wrong?
Reply With Quote
  #22  
Old 12-05-2016, 1:53 PM
Metal God's Avatar
Metal God Metal God is offline
Senior Member
 
Join Date: Apr 2013
Location: San Diego
Posts: 1,836
iTrader: 0 / 0%
Default

Quote:
instead Hatcherites believe that oiled, greased, lubricated cartridges are dangerous, they "dangerously" raise pressures, over load the bolt mechanism, etc, etc, etc. Of course this is non sense
It sounds to me oil and or grease was used on actions designed to open when fired . It makes sense they would need the lubrication . And who cares if they put a bunch a pressure on the bolt . It was going to open anyways and needed that pressure to operate .

Why would one need greased ammo in a bolt gun ? Maybe because greased ammo was used for awhile that gun makers at the time figured we should just grease them all . Can't hurt right ? Well maybe it can hurt because the bolt/action is not designed to open relieving that pressure resulting in the cartridge sliding back in that closed system creating more pressure on the bolt then should be there ????

Well that's my thinking on that .
__________________
Tolerate
allow the existence, occurrence, or practice of (something that one does not necessarily like or agree with) without interference.

Anyone else find it sad that those who preach tolerance CAN'T allow the existence, occurrence, or practice of (something that they do not necessarily like or agree with) without interference.

I write almost everything in a jovial manner regardless of content . If that's not how you took it please try again
Reply With Quote
  #23  
Old 12-05-2016, 2:36 PM
Drew Eckhardt Drew Eckhardt is offline
Senior Member
 
Join Date: Apr 2010
Location: Silicon Valley, CA
Posts: 1,917
iTrader: 2 / 100%
Default

Quote:
Originally Posted by repoman1984 View Post

Now what really cooks my brain is you have the HK mp5, with its really elaborate roller locking action then... some new companies make copies or "clones" of mp5 type carbines/rifles and they don't even bother with roller locking actions, just a spring and bolt/bolt carrier strait blowback. huh? It almost proves that the rollers were never required for that cartridge to function at all in that type of firearm.
It proves the rollers weren't necessary with that reciprocating weight and accuracy requirement.

A G3 could be run as straight blow back too, although you'd need to increase the bolt + carrier weight from 710g (vs 618g for a LR308) to 14kg.

Delayed blow back improves accuracy, both in full auto where you have less moving mass shaking things and semi auto with less bolt movement before the bullet leaves the barrel for better accuracy.

I need to install a 9mm magazine block and upper on an AR and compare the too after recovering from Gunmageddon.

Quote:
Once more there are even modern manufactured 5.7x28 strait blowback actions the 5.7 runs at 50,000psi WAY hotter than half the combat pistol rounds . This really seems half science and half marketing. Is there a scientific formula for PSI/time/resistance, modern firearms are built around?
I'd bet on total impulse.

Last edited by Drew Eckhardt; 12-05-2016 at 4:49 PM..
Reply With Quote
  #24  
Old 12-05-2016, 4:18 PM
slamfire1 slamfire1 is offline
Banned
 
Join Date: Aug 2015
Posts: 794
iTrader: 0 / 0%
Default

Quote:
Why would one need greased ammo in a bolt gun ? Maybe because greased ammo was used for awhile that gun makers at the time figured we should just grease them all . Can't hurt right ? Well maybe it can hurt because the bolt/action is not designed to open relieving that pressure resulting in the cartridge sliding back in that closed system creating more pressure on the bolt then should be there ????
No one designs a structure to fail with less than rated load. No one designs a bolt rifle or a gas gun, assuming the cartridge carries any load. The cartridge is the weakest part of the whole system, the action and barrel are there to support the case, not the other way around. But Hatcherites believe the case is strong and the action is weak. If the case ruptures, very bad things happen, and yet, Hatcherites want to stress the case. They think the thin sidewalls of a brass case are stronger than the ½” shear path found on the typical bolt lugs. They want ripped and torn cases, they want short case life, because, they think the case is strong and the action is weak.

This sort of makes sense if you remember that the US Army built over 1,000,000 defective M1903 rifles. Their own tests showed that about 33% of them would fail in an overpressure situation, Hatcher never quantified just how many would shatter and fail with normal loads. We know of low number receivers that were so brittle that they were broken from a blow with a plastic hammer.

We know this now, but at the time, that is 1906 through 1917, the Army did not “know” it was making defective rifles. The US Army has always had an unjust culture, they shoot the messenger and they cannot admit when they are wrong. Like all large organizations, when it comes to failures, they are excuse seeking not truth seeking. You cannot trust any self investigation from any large organization, the findings will always be self serving. So while their rifles were blowing up, the Army was deigning they had a problem.

Google books has allowed examination of documents that have been lost and buried for decades. We can see the Army denial in this Arms and the Man article, written by Brig Gen Fred H. Phillips Jr

Blown Blots and Split Barrels 25 August 1917

Quote:
Recently there have been reported from rifle clubs several cases where the barrels of Army rifles have burst and where bolts have blown out. To those who are not familiar with the circumstances attending these accidents-none of which fortunately have cost human life- the mishaps have suggested that possibly the Springfield rifle is an unsafe arm, and that practice with it may be attended by fatalities.

The truth of the matter is that the Springfield is quite as safe as any high powered rifle, and possibly a much more reliable gun than one could expect from a weapon the charge of which exerts 50,000 pounds per square inch pressure in the chamber. The reason why one hears more of “blow-ups’ in the Springfield is that more rifle club members use this arm than use any other one make of commercial weapon, and consequently, in point of number, although not necessarily in point of numbers, although not necessarily in point of percentage, the accidents from the military type rifle may appear greater.

Emphatically the Springfield is not an unsafe gun. As it comes from the arsenal, it can be used year in and year out and so far as the likelihood of accidents is concerned, be as good as ever-but provide that it is properly handled and properly cared for.

If one takes the trouble to inquire into the causes of accidents with the Springfield, it will more than likely result in the conclusion that 99 our of 100 mishaps such as blown bolts and split barrels result either from the use of hand-loads or special loads improperly or carelessly put together in the making, greased chambers, or both.

In short, there nothing the matter with the Springfield as long as it is used for the ammunition for which it was designed, except of course in the very small percentage of cases where a bolt has been over hardened or some similar mechanical defect has crept in during manufacture.


This is the first reference I have found about the bug a boo of “greased chambers”. It is evident to me that the Army created a reason why their rifles were breaking, and it follows this path. Army made rifles were blowing up with Army made ammunition and since both the rifles and ammunition were perfect, being Army made, what broke them had to be a user practice. The user practice at the time was greasing bullets to prevent bullet fouling, ergo, it has to be the grease. That was the official line the Army put out in public.

Now if you do grease bullets, that grease not only goes up the barrel, but it squeezes out the back of the action, greasing the totality of the chamber walls. Such as what I did.



This was “big grease”



More examples of grease flowing all the way back to the extractor groove.



Grease is squeezed into the action areas making for a very messy rifle.






But if the rifle is properly designed and manufactured, this is not unsafe, and if ammunition pressures do not exceed the structural design limits of the action. This is why, if you ever noticed, there are pressure limits to cartridges. Exceed the pressure limits and you are stressing the action, barrel, beyond its design limits and you are risking catastrophic metal failure, sooner than later, dry or lubricated cartridges.

But, lets say you are the US Army, you know you have built 1,000,000 rifles which at least 33% are defective, and you are issuing them to unsuspecting troopers who cannot refuse their use. I consider this a morality tale. Troopers were injured with these things and the leadership decided that a trooper’s life and health was worth less than the cost of a rifle. That is exactly what it came down to. I did finally found a reference of a fatality, be it though a civilian who bought a M1903 through the DCM. The Army was issuing defective equipment, but they were not telling anyone about just how dangerous these things are. And when people are hurt, the Army is blaming everyone, everything, but themselves. And yet, we know that Hatcher knew of the production problems with these rifles from the very day it was discovered. He also knew of the corrective measures that were taken, but in Official documentation, the whole problem and corrective measures were glossed over in Springfield Armory Annual reports. So, based on what we know now, the leadership of the Army Ordnance Department had to know they had a lot of rifles that were structurally substandard, had to know their defective rifles were blowing up, but never admitted it to Congress, the public, or even, the average trooper. This is a very wicked leadership, knowingly issuing dangerous and defective equipment to its men.

No one outside the Ordnance Department really knows just how bad the situation was till Hatcher spills the beans in 1948, well after these rifles are taken out of service. Even then, Hatcher continues the party line of blaming greased and oiled cartridges. Reminds me of the Tobacco Executives who in testimony in Congress, all of them stated that they did not believe nicotine was addictive. We don’t know just how much these Tobacco Executives really believed this or not, but it is an example of how intelligent people make themselves believe lies, so as to not be rejected by the organization that benefits from the lie.

As for lubricating cases for bolt rifles, well it is not really necessary once the case is fire formed. There are certain cases, that is rimmed cases, and belted cases, where the shoulder to base distance is not regulated. These cases can and will stretch the sidewalls something terribly. I regularly fireform these cases with a lubricant on the outside. It works great on my 30-30, 303 Brit, 300 H&H and my 375 H&H Magnum. Cases are not cheap, the 300 H&H cases were about $1.75 each, I don’t see any reason why I should stress the case, limit its lifetime, and wear it out sooner. There are number of Old Economy Steve’s who disagree, but to me, money does not grow on trees. I am getting to the point that I am firing all new cases with a lubricant on the outside, I was able to buy new 257 Roberts brass, the stuff has not been on the market for years, the cost was over $1.50 a case, and on the first firing, I have been lubing the heck out of them. Once the cases were fired formed to the chamber, I bump the shoulder back 0.003”. Some actions, like the Lee Enfield, lubricating the case each firing greatly extends the case because the action is so flexible, that without lube, cases life is very short. Parashooter shows this in this article: Cases and Enfields and lube - Oh my! http://www.milsurps.com/showthread.php?t=11182&

Even for front locked bolt actions, you can make the case for case lubrication, if the case is steel or aluminum. George Frost, in his book Making Ammunition states that aluminum case ammunition is coated with a wax, just like the Pedersen rounds, to keep the things from sticking to the chamber walls. Steel case ammunition is hard on the chamber and hard on the extractor. What amazes me is as grandiose is and was the US Army Ordnance Department, they did not know that the Germans waxed their steel case ammunition in WW1. Even though this stuff was being shot in GEW98 bolt action rifles, with the strong claw extractor, they waxed their steel case ammunition so it would extract after firing.


This account is to be found in Dr Dieter Storz's book Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 https://www.amazon.com/Rifle-Carbine.../dp/390252605X The Germans fired billions of waxed steel case ammunition because steel case ammunition stuck in the chamber if it was not waxed. Just as in the Pedersen rifle, the wax would turn into a lubricating liquid when the cartridge was fired, and this broke the friction between case and chamber, allowing the steel case to be extracted without having to ram a cleaning rod down the muzzle.

So, for some case materials, specially aluminum and steel, I will bet there is a wax lubricant that the user is totally unaware of, and yet the manufacturer put on, so there would not be complaints about malfunctions.
Reply With Quote
  #25  
Old 12-05-2016, 4:50 PM
Metal God's Avatar
Metal God Metal God is offline
Senior Member
 
Join Date: Apr 2013
Location: San Diego
Posts: 1,836
iTrader: 0 / 0%
Default

I'm clearly over my head ( honestly ) How ever It would seem to me that the case does have strength and even more so when surrounded by the chamber and closed off by the bolt . OK that's not making any sense so lets put it this way . The case "adds strength to the chamber and bolt .

My thinking is if the case expands and sticks solidly to the sides of the chamber . IT must take a certain amount of force/pressure to stretch the case back to the bolt face if there is a gap between the bolt face and case head . For this lets say that pressure is 55k psi . So anything above 55k the case starts to stretch back to the breach . Now lets say in this example the pressure in the case is 62k psi .

It seems to me you would only need your bolt lugs to be able to handle 8k psi to stop the case from blowing the bolt open not the full 62k psi . Now if you make the case super slippery and it never sticks to the sides of the chamber . Those bolt lugs would have to handle much more force/pressure .

This is an assumption but if the 62k psi filled the entire chamber including the space between the bolt face and head . The head would not stretch back to the bolt face do to the equal pressure being exerted . So my "theory" is there is very little pressure between the head and bolt face when pressures are below the ability to stretch the case back and it is the case it self keeping the pressure from blow the head out .

Anyways that's my thinking on that . The case it self helps control how much force is exerted against the bolt . If you slick it up more force will be exerted against the bolt .
__________________
Tolerate
allow the existence, occurrence, or practice of (something that one does not necessarily like or agree with) without interference.

Anyone else find it sad that those who preach tolerance CAN'T allow the existence, occurrence, or practice of (something that they do not necessarily like or agree with) without interference.

I write almost everything in a jovial manner regardless of content . If that's not how you took it please try again

Last edited by Metal God; 12-05-2016 at 4:53 PM..
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT -8. The time now is 7:27 AM.




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Proudly hosted by GeoVario the Premier 2A host.
Calguns.net, the 'Calguns' name and all associated variants and logos are ® Trademark and © Copyright 2002-2021, Calguns.net an Incorporated Company All Rights Reserved.
All opinions, statements and remarks made by Calguns.net on this web site and elsewhere are solely attributable to Calguns.net.



Seams2SewBySusy