BigBoreBubba
Member
- Joined
- Jul 23, 2021
- Messages
- 184
It's generally considered too fast for rifle-length barrels and match-type loads, IMR4895 is considered the entry-level powder for even 150's in hunting loads. LIke BlueJay, I have found IMR3031 to be excellent in my short-barreled M1a, better even than IMR4895. I don't think IMR3031 is a good match for 168 or heavier bullets, however, but I'm sure there are exceptions to that, somewhere. It is likely you would see velocity benefits with a slower powder, like IMR4895, in a rifle barrel vs IMR3031.
I did a quick workup with H335 and the 150's as an alternate to IMR3031 or IMR4895 in my M1a (and in the .30-06 Garand...) it worked well enough, but showed pressure signs quickly (mashed primers,) and had a pretty good blast and fireball, at least compared to the IMR flavors. If you have a bunch with no other use for it, it's not terrible, but it's not my favorite, either. I think I settled on 41.5grn H335, #34 primer, in LC brass, under a 150grn Hornady FMJ for the .308. I consider that a near max load in my M1a. It gave me 2530fps, which is right around what my equivalent loads with IMR's 3031 or 4895 give me. I don't notice a difference under 300yds... but beyond that, the lower velocity of both the load and the short barrel start to take their toll.
I quit trying to match factory velocity with my M80 duplicate load... it put me too close to the edge. I'm at about 95% of factory and everything is peachy.
Just curious, what pressure signs were you getting with H335 at that charge weight? I did a ladder from 41.0 to 43.0 when I worked up my 155gr HPBT load. I didn’t have any pressure signs in that test. 43.5 was the listed max, so I stayed 0.5 under. I settled on 42.4 in the end.