Tweet
So, I decided to resurrect the bolt-action format for my 18" Rainier barrelled AR in 6.5 Grr, swapping out the upper and bcg to a BCA bolt action upper/bcg I had picked up a few weeks ago. Originally I had it set this way when that new upper came in, but had results that left me scratching my head (thread/post about this somewhere lol) so discontinued it while I pondered.
Conclusion I came to was that the increased MV I was seeing, around 50 to up towards 100 fps in some cases, for loads that I was positive were under 52 ksi... I'm chalking it up to that increase from gas not escaping back to cycle the bcg and just pushing the bullet on down the pipe.
Makes me also think that the mfrs that test their ammo in a "test barrel" are using a bolt-action style vice AR. I think Hornady does it with an AR, maybe AA, but hodgdon et... thinking straigh pipe.
Today I revisited all of this, with some more testing, and the results did show, again, increases in MV over what the AR was doing.
120 Tgk, load with 27.2 ArComp, in the AR 2436, as a bolt action 2476.
115 Barnes Tac-mle, 27,4 Ar Comp, in the AR 2445, in bolt 2504.
120 Pro hunter, 30.7 CFE, in AR 2453, in bolt 2487.
129 SST, 27 gr Ar comp, AR was 2346, in bolt 2421.
No brass/no primers looked over-pressure, no swipes, no shiny spots, no sticky bolt lift. Brass looked good. It should have b/c I know these loads from the ARs.
These are all candidates for a hunting load in this barrel.
I'm trying to find a good niche for this barrel, but don't need it in AR now that I'm working on a 16" (for short/light, 125 yds and under) and already have the 20 nailed down. So maybe this will be a good spot for it.
Has anyone else done anything on this? Interesting also b/c it's the same barrel as AR, and now in bolt.
Conclusion I came to was that the increased MV I was seeing, around 50 to up towards 100 fps in some cases, for loads that I was positive were under 52 ksi... I'm chalking it up to that increase from gas not escaping back to cycle the bcg and just pushing the bullet on down the pipe.
Makes me also think that the mfrs that test their ammo in a "test barrel" are using a bolt-action style vice AR. I think Hornady does it with an AR, maybe AA, but hodgdon et... thinking straigh pipe.
Today I revisited all of this, with some more testing, and the results did show, again, increases in MV over what the AR was doing.
120 Tgk, load with 27.2 ArComp, in the AR 2436, as a bolt action 2476.
115 Barnes Tac-mle, 27,4 Ar Comp, in the AR 2445, in bolt 2504.
120 Pro hunter, 30.7 CFE, in AR 2453, in bolt 2487.
129 SST, 27 gr Ar comp, AR was 2346, in bolt 2421.
No brass/no primers looked over-pressure, no swipes, no shiny spots, no sticky bolt lift. Brass looked good. It should have b/c I know these loads from the ARs.
These are all candidates for a hunting load in this barrel.
I'm trying to find a good niche for this barrel, but don't need it in AR now that I'm working on a 16" (for short/light, 125 yds and under) and already have the 20 nailed down. So maybe this will be a good spot for it.
Has anyone else done anything on this? Interesting also b/c it's the same barrel as AR, and now in bolt.
Comment