Which twist rate for 300 blackout?
- Thread starter Blue72
- Start date
Why does it need to be 16" long, especially for subsonic rounds?
I live in New York,,, can’t put an AR-15 on a pistol license. So I can only build a carbine
I prefer 1:8 to 1:7. There’s very few bullets out there that justify a 1:7 even a SMK 240 or 225 eld-m shot at 990FFP is perfectly stable (and quite accurate) in a 1:8 twist. Plus the 1:8 will be more accurate with the 110 super sonic or even the lighter LeHigh 78 CQB.
Run the numbers in the Berger stability calculator and you’ll see for yourself. Even at 0F and 0 feet altitude, you’re still stable at 1050FPS with a Hybrid 230gr which is 1.6in long.
You’re absolutely fine for the 190 sub-X and 200Lapua FMJBT.
I don’t know why Remington/AAC made the switch to 1:7 and kinda push the industry that way but it was and still is utterly retarded just like anything Remington touches post Cerberus acquisition.
People have been running short barrel 300 whisper in 1:8 twist since the early 90s with heavy 240-250gr pills. Never been a problem. And then you have the other Qtard pushing a 1:3 twist 8.6 creedmoor. Genius. Truly the next JMB.
Run the numbers in the Berger stability calculator and you’ll see for yourself. Even at 0F and 0 feet altitude, you’re still stable at 1050FPS with a Hybrid 230gr which is 1.6in long.
You’re absolutely fine for the 190 sub-X and 200Lapua FMJBT.
I don’t know why Remington/AAC made the switch to 1:7 and kinda push the industry that way but it was and still is utterly retarded just like anything Remington touches post Cerberus acquisition.
People have been running short barrel 300 whisper in 1:8 twist since the early 90s with heavy 240-250gr pills. Never been a problem. And then you have the other Qtard pushing a 1:3 twist 8.6 creedmoor. Genius. Truly the next JMB.
1:7 for subs on a 16" should be good.
I followed suit with Sig and Q and went 1:5 on my SBR.
I had not heard this one. I watched a special on the Russian VSS Vintorez shooting the 9 x 39 and they spent a lot of time on why the larger heavier bullet allowed them to better suppress the sound signature and how the round would still penetrate armor at up to 300 meters. Maybe they are just taking a page from the Russians development?
It’s dependent on barrel length. 1:5 is too fast for a 11.5” barrel even. Projectiles will come apart.
Fastest you can go on a 16” is 1:7.
More rotations the better.
Fastest you can go on a 16” is 1:7.
More rotations the better.
Two things come to mind:
1) Anything that can be done, can be overdone.
2) Just because you can, doesn't mean you should.
There's a reason that most .300BLK barrels are 1:8........because it works.
1) Anything that can be done, can be overdone.
2) Just because you can, doesn't mean you should.
There's a reason that most .300BLK barrels are 1:8........because it works.
I own 2, but subsonic ammo 190 plus is great for
The home in a short barrel and a suppressor, I also have a 16 inch barreled version however even at 100 yards it’s useless and has less energy than A 45 caliber round, and at 100 yards you’re looking at 18 inches of drop which is huge, along with the fact that if hunting is the goal forget it. Now at 200 yards if you could even make the shot you’re Now looking at 6 and a half feet of drop, And This is actual data from testing using strelok pro using real data and not factory specs off the web. For 220 gr subsonic Sig elite match. and all my weapon, and scope data, scope height etc
I also tested the 190 gr subx Hornady and at 200 yards it hits with whopping 350 ft pounds. With those numbers and the dramatic bullet drop other than shooting from a bench and paper for shits and giggles it’s a bust. You have to run supersonic ammo for any type of practical use.
If you’re going for home protection 7 1/2 to 10 inch barrel is all you need that said there’s so many more useful calibers than the 300. Its sole purpose was to be used on the 14.5 inch barreled M4, and combinations down to 7.5 inches. And equipped with a suppressor, and then those types of configurations for use indoors it’s perfect and about the quietest suppressed round I have experienced.
I another thing to take note is that in a 16 inch configuration with a 125 gr supersonic round, when the military tested then they claimed 500 yard effective range, lower the 147 inches of drop, Whether it’s kind of ridiculous, but to each his own and as I don’t know your purpose maybe you have some specific purpose for your desired configuration I’m not aware of. But if hunting or even target shooting are your goals there are about a dozen alternatives that are better.
Based on some of the people on this forum I’m sure someone will disagree or is an expert on ammunition and custom hand loading which in the case in my opinion I’m only commenting on off-the-shelf and readily available factory available and firearm components.
Best of luck on your build
they will be replacing all my pistol caliber carbines. It will be used mostly for bullseye shooting without disturbing my neighbors. Distance is about 100-125 yards. After loosing some of my hearing it will probably be my home defense gun too
I have a 16 and 7.5 and for that distance either will do, the round was intended for 14.5" and below. so for home defense go short, 16" is clumsy. get something along these lines and you'll serve both purposes with equivalent success, and honestly even a super sonic 300 is pretty much ear safe with a good suppressor. here's one of mine, people knock the polymer lower, but for $299 at the time it was a deal,, and good luck to them finding anything close nowadays. but, throw can on it and you're good, even supersonic is quiet enough for no ear protection.
Attachments
If quiet is your goal for bolt gun. Get some fast burning powder like VV N105 or AA #9
Hey i get it, but just remember the Subs drop like a rock, 16" at 100 is bizarre, all in all there not a whole lot of difference in noise. but i'd suggest trying both.
Its totally dependant on barrel length, with 300 the longer the barrel the slower the twist. You are good to go with 1:7 from 16" down to around 8". At 8" I would start to switch to a 1:6 till around a 6" barrel and below I would do a 1:5 although Q has has excellent luck with a 1:5 on a 7" barrel. SIG is running a 1:5 on the Rattler which is a 5.5" barrel. I have a custom 7.5 barrel with a 1:6 that has been very accurate with no issues.
OP I would do a 1:7 or a 1:8 on a 16". Wilson makes a nice 16" barrel in 1:7.
OP I would do a 1:7 or a 1:8 on a 16". Wilson makes a nice 16" barrel in 1:7.
The 1:3 twist in 8.6 is to slow the bullet even more to get get a better powder burn and increase energy as opposed to velocity. The wound channel is wicked af in testing.
Similar threads
