Slow (n340) Vs. Fast (n310) With 45acp

[alzo]

I typically shoot a load of 6.2gr N340 with a Zero 230gr JHP, 0.469" crimp, COL= 1.215", Winchester large pistol primers.

Recently, I was working up a lighter (i.e.- lower PF) load using N310 and measured the following on my chrono. All means are based on 20 rounds fired from 5" Kimber at 80 deg F with chrono 15 ft from muzzle.

3.9gr 754 SD=10.4 ES=45.5

4.0gr 770 SD=12.0 ES=39.3

4.1gr 781 SD=11.6 ES=38.4

4.2gr 801 SD=6.6 ES=25.2

I also reclocked my 6.2gr of N340 load in both of my 1911's and got:

Kimber: 866 SD=18.8 ES=74.2

Wilson: 859 SD=24.4 ES=79.3

I notice that the SD's and spreads are quite a bit lower with the N310. Everything else is the same with these two loads except the powder. Can anyone explain why the faster powder seems to give more consistent results ? Is that common ?

[Chills1994]

I haven't loaded anything using V V N 310, but I have used V V N 340 with 200gr LSWC. Yep, I have noticed the same thing too, larger SD's with the N 340. I don't know why, maybe it was the weather at the time.

W 231 seemed to have lowest SD of any powder I have tried so far, which really isn't much compared to others experience on this board. I have tried Bullseye, Unique, 231, V V 320, and V V 340. That's it.