Thanks for the info!!!I've been shooting 8" twist 300BOs since 2014, and have shot cast exclusively. Most shooting has been done with the Lee 155 and TL160, both lubed and cast. The 8" twist is no issue for running either of those bullets full speed. I have friends who also have 300BOs, 7", 8", and 10" twist. We've shot lighter and heavier bullets, all supersonic, and the 8" twist doesn't seem to be a hindrance. The 10" twist barrel was ordered and expected to be superior, but hasn't shot cast AS WELL as his 8" twist Hardened Arms.
I bought a 12 twist Wilson 7.62x40 thinking it would be superior due to "kinder twist" and 5-6gr increase in powder capacity, but it has yet to prove its worth in either regard. Velocity increase is minimal, and accuracy hasn't been as good. The 300Ham'r was designed for jacketed bullets, so expect more of the same.
As for a longer barrel in 300BO. There is only modest velocity increase in barrels beyond 16". Spend some time on the 300 Blackout forum and you'll see that some folks have spent a lot of time getting the most from the 7.62x35. Some guys are experimenting with as quick as 1-5" barrels!
Series | 9 | Shots: | 4 | 150 GD jax | 19.1 cfeblk |
Min | 1757 | Max | 1890 | ||
Avg | 1836 | S-D | 59.2 | ||
ES | 133 | ||||
Series | Shot | Speed | |||
9 | 1 | 1757 | ft/s | ||
9 | 2 | 1828 | ft/s | ||
9 | 3 | 1890 | ft/s | ||
9 | 4 | 1872 | ft/s | ||
---- | ---- | ---- | ---- | ||
Series | 10 | Shots: | 1 | 145GC | 16 H110 HT |
Min | 1624 | Max | 1624 | ||
Avg | 1624 | S-D | 0 | ||
ES | 0 | ||||
Series | Shot | Speed | |||
10 | 1 | 1624 | ft/s | ||
---- | ---- | ---- | ---- | ||
Series | 11 | Shots: | 1 | 145GC | 15.7 rx7 AC |
Min | 2009 | Max | 2009 | ||
Avg | 2009 | S-D | 0 | ||
ES | 0 |
To tell truth,,ive only ever owned 1 ar,,and that is a 350 legend.i avoided the stupid plastic brass chuckers,for years!!!I haven't chrono'd my 140s, but suspect they are close to 2100fps. 160s at 1920fps held accuracy to at least 500m, so what do you need the load to do?
110Vmax will go 2400fps, maybe a bit faster in 16", but I suspect heavier bullets will fare better beyond 200 yards.
If you're going to shoot supers only, go with 8 twist and carbine gas. Pistol gas will need an adjustable gas block.
those RL7 and H110 velocities look to be transposedSome chrony data, 18" carbine. Some loads I tried, none trying for max.
Series 9Shots: 4150 GD jax 19.1 cfeblk Min 1757Max 1890Avg 1836S-D 59.2ES 133Series Shot Speed 9 1 1757ft/s 9 2 1828ft/s 9 3 1890ft/s 9 4 1872ft/s ---- ---- ---- ---- Series 10Shots: 1145GC 16 H110 HT Min 1624Max 1624Avg 1624S-D 0ES 0Series Shot Speed 10 1 1624ft/s ---- ---- ---- ---- Series 11Shots: 1145GC 15.7 rx7 AC Min 2009Max 2009Avg 2009S-D 0ES 0
150 SP turned some good numbers too:
2260 avg, ES=12 IIRC, H110. Have to look for cfeblk as I have some chrony data for it, didn't remember using it all.
I was looking specifically at the H110 and RL7 numbers; they appear transposed.They might be, I annotated after the fact. Don't have any cfeblk left, guess I used it all. Those zinc's should go real fast. IRC Ian was doing that for 223?
and there is the drawback to the 300 Ham'r, magazine length is a limit to powder capacity due to ogive lengthAny experience with Sierra 125 Game Changers?
I picked up 200 ta try in the HAM'r.
But man there profile makes for compressed loads trying to maintain 2.260.
CW
I have a few boxes of 125 SST I find them fragile @ 2200 fps in Blk Out on Whitetails. In lung shots they are devastating. On bigger bones iffy.125gr TGK? Yup, lots of bearing surface on that one. Better choice would be the 125SST, unobtanium.