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#1




How to calculate psi and ft/lb?
Hey all I'm relatively new to reloading and I'm aware of how important pressures are to this hobby, I often see psi numbers and ft/lbs, for example 362 ft/lbs 18500 psi, is there an equation on how to get these based on powder charge, projectile weight, gun weight? Thanks guys.
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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#2




I would think muzzle velocity would be your best bet. Quickloads could give you a close estimate as well I would think.
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#3




Thanks howuch is that program? I'd like to know the formulas they use to get those numbers, I doubt it's that difficult, I could be wrong.
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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#5




Quote:
https://www.xdtalk.com/threads/relat...recoil.221369/
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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#7




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Anyone know how those numbers are calculated?
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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#8




Reading your posts this is exactly what you are looking for. Kinda pricey but well worth it.
https://www.neconos.com/details3.htm
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Good friends will come bail you out of jail. A best friend will be sitting next to you in the cell saying damn that was fun! 
#9




Ft lbs is torque, which is how they're measuring recoil, so if you're asking about ft lbs, you're asking about recoil.
All those numbers are either indirectly measured or estimated. Velocity is much easier to measure than pressure, so that gets used the most. Is your question how to measure pressure? 
#10




Sorry, your link was pretty much all about recoil.
There's a few calculators out there. http://reloadammo.com/footpound2.htm "Energy = Weight times Velocity Squared divided by 450395 (fixed constant)" 
#11




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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#12




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WTB 3rd Gen SW also looking for a 22 pistol with 6" bbl or longer 
#13




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As superdave showed. It is simply a measurement of energy potential. Also used, and shown in some reloading manuals as a "lethality" indicator. Or "how hard" a given bullet at a given velocity HITS the target at given distances. PSI, on the other hand, as noted, is a "pressure/force" indicator. At lower levels like water or air pressure. Simple to use a gauge. At firearms pressure level. Not so simple, and impossible to measure with a mechanical dial gauge. Also far to many variables to be able to reduce the measurements at that level. That happen in thousandths of a second to any equation. In early firearms developement "copper crushers" were used. Where a tiny copper ball of a given diameter was subjected to the pressure until it deformed. Then the deformation was measured and used to calculate the pressure required to cause the deformation. That was known as "CUP" [copper units of pressure]. Explained in this link. https://en.wikipedia.org/wiki/Copper_units_of_pressure Now it is done "electronically". Using either "strain gauges" or "piezoelectric cells". Which measure the massive force levels in thousandths of a second. Electricity depending on the medium it is moving in. Travels at about 280,000,000 meters per second. In a 12 gage copper wire. Much faster than any bullet. And also far beyond the capability of any hobbiest reloader. Unless you have tens of thousands of dollars to spend setting up your own ballistics lab. 
#14




How to calculate psi and ft/lb?
$700 will get you the software and hardware you need to test pressure in a gun.
https://www.shootingsoftware.com/mm5...tegory_Code=PT I am sure there are others out there. You then need to scratch a small spot on your gun barrel to glue the sensors (strain gauge) to. A Thompson center contender with the barrel in the caliber of your choice is perfect for the job that way you don’t destroy your gun. Just a tiny spot on the contender barrel behind the rear sight it’s almost not visible Mike Sent from my iPhone using Tapatalk
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#16




Quote:
In ballistic calculations, many people try to relate muzzle energy to how powerful a bullet is in terms of "hitting power". This is one way to compare the potential of a bullet to cause damage to a target but it's got limitations. To calculate muzzle energy, you use the formula 1/2*m*V^2 Where m= mass of bullet V = muzzle velocity V^2 = Velocity * Velocity This is the kinetic energy of the bullet at the muzzle. We usually measure the mass of the bullet in grains and the velocity in feet per second. These do not instantly translate into footpounds, but the conversion isn't too difficult if you know these two numbers. To convert bullet weight and muzzle velocity into footpounds, you use the 1/2*m*V^2 formula but you have to convert the bullet weight into "slugs" where 1 slug = 225,218 grains. This webpage makes it easier to translate bullet weight and muzzle velocity into footpounds http://www.larrywillis.com/bulletenergy.html For comparison: in the UK, pellet guns are limited to 10 footpounds before they require licenses to own. A typical 22LR that shoots a 40g bullet 1100 fps has a muzzle energy of 107 footpounds A 120g 9mm bullet with a MV of 1100 fps has 322 footpounds of energy A 120g .357 bullet with a MV of 1400 fps has 522 footpounds of energy A 55g .223 bullet at 3000 fps has 1098 ftlbs of energy A 150g .308 bullet with 2760 fps has 2567 ftlbs of energy Energy is simply the potential of a bullet to cause damage. If a 3000 fps .223 bullet passes clean through an animal and does not expand, tumble or fragment, very little energy is deposited into the animal. It's easy to measure muzzle velocity. You just need a chronograph. What you feel with your hands or against your shoulder (recoil) is more related to bullet momentum which is the mass of the bullet times the muzzle velocity (plus burned powder mass times velocity) This is a calculation of exterior ballistics. Calculating pressure within the cartridge or gun is a matter of interior ballistics. This is more complicated and best left to reading load data manuals although you can estimate maximum chamber pressure with some software (Quickload) or measure the pressure with a device like Pressure Trace although you shouldn't bother with this unless you really know what you're doing and want to go really deep into interior ballistics. If you follow published load data, work up your loads and stay below the maximums, you'll certainly be good to go for a long time. With more research and experience loading, you can go as deep as you wish. No need to go this deep when you're just beginning. 
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