herkyguy
Member
- Joined
- Jul 31, 2009
- Messages
- 1,409
I’ve been tinkering with an MPX for quite some time now. 13.5” barrel with a 2.5” flash suppressor to keep it legal.
Initially tried 800X with 147 grain FPs, but at max load only got about 900 FPS. Frustrated at first, I’ve come around to liking them as they’re very quiet and minimal recoil. I’m thinking they’d be good for indoor use.
but the goal was always to really optimize the longer barrel. Finally cracked open a can of AA#7 and found some 125 grain Sierra V-Crown HPs. Not my first choice, but the hoarding of late has diminished the available supply. Initially a little concerned since I’ve read those bullets are made for the .357 Sig, but my Lyman manual had a load for them with #7.
Shot them today. Fed, fired, ejected with no problems. At 7.2 grains, I’m on the low end with a max recommenced at 7.8, and got an avg of 1248 FPS, with a SD of 8 FPS.
Obviously much louder. Felt recoil was minimal, no muzzle blast. Good accuracy at 20 yards, although I didn’t take the time to measure.
Question is, would there be much gain by upping the powder load? Can’t find any data on the upper limit of those bullets for reliable expansion. Pretty sure I’m good at 1250, but open to suggestions.
photo not from today’s session.
Initially tried 800X with 147 grain FPs, but at max load only got about 900 FPS. Frustrated at first, I’ve come around to liking them as they’re very quiet and minimal recoil. I’m thinking they’d be good for indoor use.
but the goal was always to really optimize the longer barrel. Finally cracked open a can of AA#7 and found some 125 grain Sierra V-Crown HPs. Not my first choice, but the hoarding of late has diminished the available supply. Initially a little concerned since I’ve read those bullets are made for the .357 Sig, but my Lyman manual had a load for them with #7.
Shot them today. Fed, fired, ejected with no problems. At 7.2 grains, I’m on the low end with a max recommenced at 7.8, and got an avg of 1248 FPS, with a SD of 8 FPS.
Obviously much louder. Felt recoil was minimal, no muzzle blast. Good accuracy at 20 yards, although I didn’t take the time to measure.
Question is, would there be much gain by upping the powder load? Can’t find any data on the upper limit of those bullets for reliable expansion. Pretty sure I’m good at 1250, but open to suggestions.
photo not from today’s session.
