imported Vs KF ammunition - pressure statistics...

[ssmickey.32]

Dear friends,
In pursuit of my knowledge about weapons and ammunition, I came across a very interesting point. Kindly enlighten me on the subject...

The maximum pressures of cartridges are as follows:
32 S&W Long cartridge – max pressure is about 14,000 PSI
.32 H&R Magnum cartridge – max pressure is about 24,000 PSI
.327 Magnum cartridge – max pressure is about 45,000 PSI

however, our KF ammunition .32 cartridge on field gun website says mean Max pressure of 46.4 MPa which is equal to approx. 6730 PSI

[conversion: 1 MPa = 145.03773 PSI]

but the word ‘mean Max’ is used on the website. That means it is mean of max pressure & min pressure. Max pressure.. i presume.. is Chamber max ammunition explosion pressure, what is the minimum pressure… Chamber exit pressure or muzzle exit pressure?

Even otherwise a mean pressure of 6730 PSI is well below the S & W .32 long cartridges having max pressure of 14000 PSI.

Does it not indicate that our KF ammunition is very weak... or in other terms of design pressure, it is unsafe to use S & W .32 long cartridges in IOF Revolvers…

Kindly clarify…

Best regards…

ssmickey.32

[winnie_the_pooh]

Guess what? The head stamp on KF ammo reads

".32 S&W.L"

[Anand]

While I don't have the exact numbers noted down I had "chrony"ed the .32 S&W Long cartridges and in six shots the velocities ranged from 748 fps to 922 fps (yeah I know ) through my W&S Mk IV 4" Barrel revolver.

My understanding is that the powder is metered by volume (as is most factory ammo) rather than weight at the time of production. If this process is not consistent then the powder charges will vary enough to cause inaccuracies. Now here is the kicker, the bullets are pretty okay by weight, with variances of not more than about a couple of grains. (95 gr+/- 2 gr.)
But this will obviously be magnified when added to the powder variances!
Anand

[MoA]

Anand: A lot of the uber accuracy folks swear by metering powder by volume. It isnt as inconsistent as one might believe, especially with powders that meter well.

However given the extreme spread in velocities that you are witnessing my guess would be that the IOF powder does not meter well. Given the small case size of the .32 even a couple of 10ths of a grain would explain the vairiance I would guess.

BTW when loading pistol calibers, I personally use the volume method, and wieght check only about every 20th cartridge.

Rifle reloading is a whole different ball game for me.

[Risala]

While I don't have the exact numbers noted down I had "chrony"ed the .32 S&W Long cartridges and in six shots the velocities ranged from 748 fps to 922 fps (yeah I know ) through my W&S Mk IV 4" Barrel revolver.

My understanding is that the powder is metered by volume (as is most factory ammo) rather than weight at the time of production. If this process is not consistent then the powder charges will vary enough to cause inaccuracies. Now here is the kicker, the bullets are pretty okay by weight, with variances of not more than about a couple of grains. (95 gr+/- 2 gr.)
But this will obviously be magnified when added to the powder variances!
Anand

I am presuming that this was ammo by KF....does anyone have a chrony in Del...like to try out .32 ACP both KF & S&B and compare the results...