.308 Sub/Super Combo

[Wall_Hanger]

I am looking into putting together a "nicer" .308 bolt gun that will be shot suppressed. I am curious what twist rate would be best for shooting a combination of subs and supers. The goal is to have a gun that can shoot inside 100yds subsonic for doe patrol and pig work and then shoot supers for larger bucks, mulies, and perhaps elk. The focus will be on supers as far as accuracy is concerned since that will be the longer shots. I am new to the subsonic game so any help is greatly appreciated. I am not overly worried about weight so to the extent barrel length is a factor I am happy to go out to 20" or more if that is where the compromise is.

I am not married to the 308 caliber but being that I don't load I like the ability to get subs off the shelf. I may get into loading in the future but not right now.

[ABroussard]

1:10 will do it. Discreet ballistics recommends 1:10 for their subs also.

[Wall_Hanger]

1:10 will do it. Discreet ballistics recommends 1:10 for their subs also.

Thanks for the quick reply. Any comment/thought on length? Prefer 18" if doable but can go longer for better overall performance.

[ahlongslide]

I would just go the same twist rate as 300blk and do a 1:8. But I like to use the heaviest projectile when going subsonic, my current ones are 240SMK
And I like short barrels with suppressors, so I'd do 16"- but 18" is a good compromise
1:10 will stabilize almost anything, but I don't risk it with a can on the end.
Overstabilization isn't as big of a problem as most attribute to it, Brian Litz wrote a great article on it (...if I can find it...).

Personally, I think you should have a short/light 300blk for subsonic 100yd killing and a different supersonic gun for long distance and elk, because, hey, two guns are better than one.

Good luck on the build!

[TX03RUBI]

1-10 is going to be the best overall combination. It’ll handle up to 205-208 Gr subs well while still shooting the 168 class projectiles well. They usually handle the 150-155s ok as well.

[Mike D]

.308 Sub/Super Combo

Like Rubi said 1:10 will work but not ideal. For subs I want the heaviest projectile I can get. A 220 grain Bullet at subsonic velocity carries about the same energy as a 45 ACP +P round. I would want a 1:8 twist to be able to shoot 240+ grain bullets and know they will stabilize.

Since it’s a sleeker bullet it carries the energy farther but is still is only about 500# at the muzzle.


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[Wall_Hanger]

Like Rubi said 1:10 will work but not ideal. For subs I want the heaviest projectile I can get. A 220 grain Bullet at subsonic velocity carries about the same energy as a 45 ACP +P round. I would want a 1:8 twist to be able to shoot 240+ grain bullets and know they will stabilize.

Since it’s a sleeker bullet it carries the energy farther but is still is only about 500# at the muzzle.


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So for supers the 1:10 will be good but it will likely be a bit lacking for subs? I’m actually ok with that since my primary focus shooting subs will be hog/doe patrol at pretty close range. I just want to make sure it’s stable enough to not damage the can leaving the barrel.

[oneisnone]

.308 Sub/Super Combo

My favorite gun I ever built and regrettably sold was a .308 bolt pistol with a 1/7 Shilen barrel cut to 11.5". I shot 220gr subs out to 400 yards accurately and shot 178gr supers out to 875 yards with no problems, both running an omega can (not in picture)

[kck]

So for supers the 1:10 will be good but it will likely be a bit lacking for subs? I’m actually ok with that since my primary focus shooting subs will be hog/doe patrol at pretty close range. I just want to make sure it’s stable enough to not damage the can leaving the barrel.

Here's a 308 I built for myself with a 16.5" 1:10 Rock Creek. I killed around 160 does on the golf course here in La Grange with 175 Match Kings behind 10.1 grains of TrailBoss (all head shots from 50-60 yards) and, on paper at 60 yards, shot 1/2" groups. That round has enough pop at 60 yards to enter on the bridge of the nose and come out the back of the head with a VERY audible whiz. I shoot the same bullets (Bergers as well) behind 44 grains of Varget and they shoot quite well. Guess what I'm saying is that shooting the real heavies obviously carries more pop but that combo I mentioned will stone cold kill anything on head shots. However, I do NOT have experience with subs and shooting animals in the body cavity so the other fellas may be able to speak to that much better than I can.

[Mike D]

.308 Sub/Super Combo

So for supers the 1:10 will be good but it will likely be a bit lacking for subs? I’m actually ok with that since my primary focus shooting subs will be hog/doe patrol at pretty close range. I just want to make sure it’s stable enough to not damage the can leaving the barrel.

Yes you will be good on supers.

I’d keep subs 220 grains or under. And test fire them without your can to make sure they are stabilizing.


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[Notaguide]

Shooting a AAC R700 16.5" (1:10) suppressed. Not too interested in subsonic due to price compared to whats offered in 300BO. FMMG 168gr shoot really well but haven't had much pass thru on deer or pigs taken. No barn burner averaging 2474fps. but did well at 505yrds. My 10yr old loves shooting it with little recoil. He hammered a 200# boar Sunday morning in the front shoulder and lost him with zero blood after running 100yrds into S.TX brush. Pretty good video of it though.

[Take em]

1:10 twist should do well.

I have a scope with external turrets and dope the sub bullets based on distance and carry both rounds with me.

These three received 200gr expanding subs in the head and body at 50-60 yards. Just have to shoot them in the head or like you do with a bow as the bullets does not give the same energy dump with sub-sonic ammo.






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[Wall_Hanger]

1:10 twist should do well.

I have a scope with external turrets and dope the sub bullets based on distance and carry both rounds with me.

These three received 200gr expanding subs in the head and body at 50-60 yards. Just have to shoot them in the head or like you do with a bow as the bullets does not give the same energy dump with sub-sonic ammo.






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That’s a good looking setup, what are your build details?

Hear ya on shooting them like you are bow hunting. Most of the subsonic work will be neck/head shots I’m sure but having the option to carry supers and subs, dope the scope and do both is about as much flexibility as you could ask for. If I’m going out for mulies or elk, I’m not too worried about bringing subs. If I’m sitting in a blind it would be nice to bring my 257 wby and a 308 loaded with subs.

[Take em]

Remington 700AAC 16.5” Barrel, Jard Trigger, Mark 5 scope. I load a super and follow it with subs so I can easily Change bullets out if needed but have full supers on the way to the blind so I can shoot deer if needed.


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[TX03RUBI]

Yes you will be good on supers.

I’d keep subs 220 grains or under. And test fire them without your can to make sure they are stabilizing.


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I never could get 220s to shoot from a 10 twist. Lots of keyholing. It’s been 8 years or so since I went down that rabbit hole, but I believe that the 208 amax was about the limit for the 10 twists I ran at subsonic velocities.