30BR and twist for subsonic load

[casspir]

I want to use the 30BR with a suppressor. I am not too familiar with the caliber but read that it would be a great tactical caliber. If I use 185gr bullets and down load to achieve velocity of less than supersonic what Twist would you guys recommend 1:12? I am not going to use it for BR. Therefore, extreme accuracy is not that important.
Thank you.

 

[P1ZombieKiller]

if you want a 308 caliber subsonic gun, why not go with the original and get a 300 whisper or a 300/221? I have one and it shoots great. 3/4" - 1" groups at 100.
Mine is a 7 twist shooting 200+ grain bullets.

 

[25AI260]

i know less about this subject but would like to guess.. with little mv i'd be thinking you'd need a really fast powder an a lot of revolutions to keep the bullet afloat--probably an 8 tw

???

but what would be tactical about 185 gr bullet with a muzzle velocity of 1050 an drop'n -211.61 inches going 912 fps, 350lbs of energy left out @400yrds

 

[P1ZombieKiller]

There is nothing tatical about any subsonic gun other than ... well... it's subsonic. With that comes the ability to hide your position upon firing your weapon. My best 200 yard group with my 300/221 is a nice 3" group. I don't think that is tatical at all. I have this rifle so that with the aid of a supressor, I can fire it with the ability to hide my position. I intend to use that to my advantage when hunting pigs here in Texas.

I personally would not shoot anything less than a 200 grain bullet as velocity has to remain slow while you need as much knock down as possible. I wished I could afford to buy 240 grain SMK to shoot as those help with knock down. I use Lil Gun powder in my 300/221 loads, and try to keep them around 1050 fps.

 

[willsnipe]

Like every other twist question, the answer depends on what length bullet you intend to use. Conventional wisdom is the heavier (longer) the better. I've shot subsonic 308s fairly extensively, & most 180s stabilize reasonably well with a 12 twist, though groups were better with a 10. If I were building a dedicated subsonic rifle, I'd use a faster twist. From all I've seen and read, 8 seems to be the most popular choice, followed by 7 and 9 in that order. If you intend to use VLD bullets, spin 'em as fast as you can. They tend to be WAY long for their weight.

 

[casspir]

Thank you very much to all who participated here. My apologies, you are correct, the use of the word “tactical” is incorrect but I have used it because of a lack of lingo. (English is my second language) I would like a subsonic caliber for culling on a Game Ranch in Africa, not causing any extra unnecessary stress to other Game. I have a 308 with an INCH action. The barrel fixing system allows a quick and precise exchange of barrels, each one keeping its initially zeroed point of impact. I would not like to go to the 300 Whisper or 300/221 as I would need a new action because the 300 Whisper or 300/221 has a smaller bolt face. I don`t doubt that the 300 Whisper or 300/221 might be a better option but for my application the 30 BR would make more sense. If however the 300 Whisper or 300/221 with a 1:8 twist is just way better I suppose a new gun is the way to go. Again thank you all for your contributions.
Wes, I enjoyed your website.

 

[canderson]

I have a 8tw 300/221 barrel, it will shoot the 220 RN and 240 SMK about 1MOA @ 100 yds. A friend of mine has had several subsonic rounds and his favorite one is a 16" 8tw .308 barrel. He shots 220-240gr subsonic(trailboss powder) and 125 ballistic tips supersonic. He has found a way to sight the two loads in his scope without changing the zero. I would look at a 7 to 8 twist and go have fun. The subsonic stuff is a blast to shoot. Usually I can hear the bullet smack the animal.

 

[P1ZombieKiller]

Wes, I enjoyed your website.

Thank you. I have not updated it in a while. Been way too busy on other stuff. Since we know what you are trying to do now, I think a 308 fast twist barrel ( 1:7 - 1:8 ) would better suit you. Much easier to find brass, a lot easier to get chambered, and there are already many proven subsonic loads out there that are safe and easy to duplicate.

 

[eww1350]

+1 for the 8 twist and use Lapua 200 grain 30 caliber sub-sonic bullets..the lapua bullets are made specifically for sub-sonic loads...have your gunsmith throat your chamber for the longer bullet...You can buy them from MidwayUsa...


Eddie in Texas

 

[FilippoMo]

You could get an extra bolt for your inch with the .223 face.
I will be cheaper than going to a dedicated rifle.
Sincerely
Filippo

 

[P1ZombieKiller]

+1 for the 8 twist and use Lapua 200 grain 30 caliber sub-sonic bullets..the lapua bullets are made specifically for sub-sonic loads...have your gunsmith throat your chamber for the longer bullet...You can buy them from MidwayUsa...


Eddie in Texas

Eddie,
I don't know much about subsonic 308 loads, but don't you want the case to be filled as much as possible? and so you would not want a long throated chamber? I know in my 300/221 the bullet seats 1/2 way down the length of the brass. Can you explain to me if it is different in the 308 subsonic loads.

 

[eww1350]

I don't think having the bullet loaded into the case body is a good idea...you can use TrailBoss powder and take up the majority of the case volume...throat length does not have to be excessive just long enough that the bullet base is even with the case shoulder/body junction...