About four weeks ago one of the local suppliers had some Alliant 300MP powder in stock so I bought a pound to try it out. Alliant lists 18.6 gr as the maximum charge for a 158 gr GDHP which I reduced by 10% to 16.7 gr for a starting load and 17.7 as an intermediate load if the lower load did not indicate any excessive pressure.
I finally got the range on Sunday to test them.
- Gun = Marlin 1894C 18.5" barrel
- Bullet = Magtech 158 gr JSP
- Case = Federal 357 magnum
- Primer = Winchester Small Pistol
- Powder = Alliant 300 MP
- Ambient temperature = 90F (prox)
Results from five measurements (feet/second):
|Charge in grains||Average Velocity||Standard Deviation||Maximum Velocity||Minumum Velocity|
None of the primers or cases showed any more indication of pressure than normal for a 357 magnum. In fact the Amercan Eagle 158 gr JSP (which clocked at almost exactly 1800 fps) had much flatter primers than the 300MP reloads.
All in all I am pretty impressed with the potential of this powder in a carbine.
No accuracy reports yet. About the time I was getting ready to try some guy started banging away with a neutered version of an M1919 and kicked up so much dust I just packed up and went home.