|
Gunsmithing & How To Pro, Amateur & WECSOG and Tutorials, Guides & OLL Build Instructions |
|
Thread Tools | Display Modes |
#1
|
||||
|
||||
AR15 barrel not fitting in receiver
I'm building my first ar15 and I've seem to run into a roadblock. I've got a 16" .223 barrel from Black Hole Weaponry, and an upper receiver from JD Machine Tech. When I try to slide the barrel into the receiver it only manages to slide in about 1/8" before it's too tight to go any farther. I've seen posts of people having a hard time getting the last bit of the barrel seated, but never seen anything about one getting stuck as soon as mine. Has anyone else had this problem or know of fixes?
I was thinking of putting the barrel in the freezer and heating my upper receiver with a hairdryer to maybe give myself a bit more play. If that doesn't work should I start scotch brighting my barrel extension? Any recommendations would be appreciated! |
#2
|
|||
|
|||
measure the diameter of the receiver.
measure the diameter of the barrel extension in three different areas and then post the measurements.
__________________
Been gone too long. It's been 15 to 20 years since i had to shelf my guns. Those early years sucked. I really miss the good old Pomona Gun Shows. I'm Back. |
#3
|
||||
|
||||
A little grease and make sure the pin is at 12 o'clock.
__________________
There are 3 kinds of people in this world. The wise, learn from the mistakes of others. The smart, learn from their own mistakes. The others, well......they just never learn. "Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it, almighty God! I know not what course others may take; but as for me, Give Me Liberty, Or Give Me Death!" Patrick Henry. |
#4
|
|||
|
|||
Scotch bright on steel does nothing but polish it. You won't remove any material to make a difference. And the barrel extension is not the place to focus your attention. Just be sure it's free of any surface defects like burrs, & dings. I would rub a little scotch bright on the ID of the receiver and use a little bit of lube.
|
#7
|
||||
|
||||
400 grit rolled up on a mandrel. Put it in the drill press and sand down the inside of the upper receiver neck until the barrel wants to start going. A lil lube and tap it in with a rubber dead blow hammer. No harm in removing a little anodiziation inside the neck. My bet is thats why its tight. Sometimes when the uppers are anodized it adds a little to much to the surface of the aluminum. Hope this helps.
|
#8
|
||||
|
||||
Haha, yeah I removed the barrel nut first...
I don't have a pair of calipers myself, so I'll try to borrow one and get back to you guys. In the meantime I'll try the grease and rubber mallet and see how that goes. |
#9
|
||||
|
||||
Quote:
The barrel extension I'm getting .998 .998 1.000 The numbers are saying that it's not going to fit, so what are my options? |
#10
|
||||
|
||||
JD receivers can be a little tight (really tight).
Could be the coating or over tight tolerances. Hit the inside of the receiver with some fine wet/dry sand paper and put the barrel in the freezer over night. Just remove a little of the finish, don't need much. Hit the extension a little too, just to knock down the rough spots. Lube the barrel extension and tap in with a rubber mallet while protecting the crown. Repeat the sanding process if needed. It is easier to remove a little at a time than try to put it back. MAKE SURE IT IS GOING IN STRAIGHT! I don't like to use power tools because its easier to F#@k things up in a hurry. If you are in SD, call JD they may help. Michael
__________________
01 FFL, Chula Vista, CA www.westcoastsurvivalarms.com info@westcoastsurvivalarms.com |
#12
|
||||
|
||||
I would contact JD machine and see what they have to say. They may just replace the upper receiver for you. The second you take sand paper or something to the receiver, JD will most likely not help you out on it anymore.
__________________
A sword never kills anybody; it is a tool in the killer's hand. – Lucius Annaeus Seneca, c. 4BC - 65AD.
|
#13
|
|||
|
|||
IF you force it in, you may not be able to remove it. I would sand till it goes in with a slight resistance.
So, what is off spec? the reciever or the barrel? Whichever one would be the one to alter. |
#14
|
||||
|
||||
You are not going to get a slip fit with .005" of interfierence. Not even if you sand all the way through the anodize of the upper to raw material. Something is out of spec (probably the upper) I would contact JD and get it replaced.
|
#15
|
||||
|
||||
I have two BHW barrels and both were pita to get in .had to buff the barrel extension off to get them in and they were still tight but not as bad
The barrel extension should be 0.9980/0.9995 The upper receiver bore is 0.999/1.000 for the first inch I think Last edited by chasjr1; 11-09-2012 at 7:34 PM.. |
#16
|
|||
|
|||
The coating doesn't make that much difference. Hard anodize is only .0005/side build up, so .001 on the inside diameter. It's difficult and unusual to get even .001 build up per side. I get my stuff done at the same place JD does.
Another thing - sometimes calipers are not accurate when measuring inside diameter. If you or a friend has something with a know inside diameter, check that also for reference. I keep a special set of calipers just for inside measurements.
__________________
There are some people that it's just not worth engaging. It's a muzzle BRAKE, not a muzzle break. Or is your muzzle tired? |
#17
|
||||
|
||||
I'm having the same issue as you, OP - my barrel is a new, lightweight, Melonited BHW 16" 5.56 copy and it won't fit in my Mega 3H upper, at all. Meanwhile, I test fit another barrel (from Adams Arms) and it goes 2/3 of the way into the Mega upper just fine, which is enough for the barrel nut to take hold. No go with the BHW barrel.
So, it is the BHW barrel(s) that is(are) the problem. Perhaps someone should call and ask them WTF? |
#18
|
||||
|
||||
Well, I ended up getting the barrel in! I used scotch bright on the barrel extension and the upper receiver, then dropped the barrel in the freezer and heated up the upper with a hair dryer. Took the barrel out of the freezer, put some grease on it, and it slid right in.
Now comes problem #2 in my first ar build. I get the barrel nut on; I put on my YHM low profile gas block; I put on the phantom flash hider; and my final piece to install is the 13" Troy Alpha rail. I slide it on and I can't get the teeth of the barrel nut into the groove that they need to get into so the rail turns into place. It seems that my barrel nut just needs to be sticking out 1/16" more from the upper receiver for the alpha rail to be able to lock in, but alas it doesn't... My assumption is that my barrel nut must be a little out of spec or something. It was just a cheap $10 barrel nut from riflegear.com so it's possible right? Tomorrow I'm going to head up to San Jose and see if any shops up there have a standard barrel nut that doesn't cause this problem. I'll post an update with my results. |
#19
|
||||
|
||||
Quote:
|
#22
|
||||
|
||||
I have a BHW barrel and a Vltor MUR upper and it was tight, but didn't have that much trouble getting it installed.
This is all I really had to do... http://www.youtube.com/watch?v=84VTpDne-XQ
__________________
ExtremeX |
#23
|
||||
|
||||
Quote:
I agree, better tight than loose. |
#24
|
|||
|
|||
Quote:
|
#25
|
||||
|
||||
A tight fit is always preferred over a loose fit.
5-10 seconds with a propane torch on the front of the receiver and it will open right up so any barrel will slip right in. Just make sure you align the index pin and slip the barrel all the way into the receiver before it cools. Cooling the barrel won't really make much difference as the thermal expansion/contraction of steel is so much lower than aluminum.
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. |
#27
|
|||
|
|||
Quote:
|
#28
|
||||
|
||||
Put the barrel in the freezer.
Sent from my DROID RAZR using Tapatalk 2
__________________
|
#29
|
||||
|
||||
for your own education, take a barrel and measure the diameter of the barrel extension with a 0.0001" capable micrometer.
Now freeze it and measure it. Then, take a receiver and measure the inside diameter where the extension slides in. Now heat it up 300 degrees and quickly measure the inside diameter again. After all that, tell me if it even matters if you put the barrel in the freezer at all...
__________________
Randall Rausch AR work: www.ar15barrels.com Bolt actions: www.700barrels.com Foreign Semi Autos: www.akbarrels.com Barrel, sight and trigger work on most pistols and shotguns. Most work performed while-you-wait, evening and saturday appointments available. Last edited by ar15barrels; 11-16-2012 at 6:14 PM.. |
Thread Tools | |
Display Modes | |
|
|