8 twist 308 ???

[Eric Leonard]

may do a 308 for my Tac 30 repeater rifle to host a suppressor, if I do the 8 twist to shoot the heavy bullets subsonic is there any chance it will still shoot something like the 175 SMK supersonic I figure there will be trade offs somewhere I’m just trying to figure where to draw the line on what twist to use and how heavy I’ll be able to load the subs and how light I’ll be able to load the supers ,,
If the 175 will shoot in the 8 would be great if I need to move to a 10 it’s gonna limit what bullets I can shoot subsonic.

 

[Will Henry]

I think there is a good chance it would shoot just fine. GD

 

[Oso]

Yes. I know a guy who shoots the 175 SMK both as supersonic and subsonic out of 300BO. The 1:8 twist will get you into the 200gr class bullets for subsonic.

 

[AckleymanII]

I know a guy that has a couple of 6 Twist blanks he would sell.

 

[cmillard]

You will do just fine. My 8" twist criterion shoots beautiful and will shoot the 175s just fine

 

[dellet]

With an 8 twist you will be able to shoot subs easily into the 220 grain weight. Above that it depends on the bullet. Copper solids like the 194 Lehigh can be a problem. Very long for the weight.

The 175 SMK will be fine both sub and super. With work you can get +/- MOA both sub and super.

With light supers you will need to pay attention to barrel heat. At 3000 fps you start hitting max spin for some bullets, 270,000 rpm. At 3350 you break 300,000. At those speeds fast shooting you can start losing bullets. If they come apart in your suppressor, it gets expensive.

It’s worth it to really think about what your shooting habits are when you start trying to shoot both sub and super. If you want Tack driving accuracy, pick one or the other. Thats your first and biggest compromise, trying to shoot both to their full potential.

 

[Eric Leonard]

With an 8 twist you will be able to shoot subs easily into the 220 grain weight. Above that it depends on the bullet. Copper solids like the 194 Lehigh can be a problem. Very long for the weight.

The 175 SMK will be fine both sub and super. With work you can get +/- MOA both sub and super.

With light supers you will need to pay attention to barrel heat. At 3000 fps you start hitting max spin for some bullets, 270,000 rpm. At 3350 you break 300,000. At those speeds fast shooting you can start losing bullets. If they come apart in your suppressor, it gets expensive.

It’s worth it to really think about what your shooting habits are when you start trying to shoot both sub and super. If you want Tack driving accuracy, pick one or the other. Thats your first and biggest compromise, trying to shoot both to their full potential.

22” 308 shooting 165s minimum I doubt anything being over 2750.

 

[urbanrifleman]

may do a 308 for my Tac 30 repeater rifle to host a suppressor, if I do the 8 twist to shoot the heavy bullets subsonic is there any chance it will still shoot something like the 175 SMK supersonic I figure there will be trade offs somewhere I’m just trying to figure where to draw the line on what twist to use and how heavy I’ll be able to load the subs and how light I’ll be able to load the supers ,,
If the 175 will shoot in the 8 would be great if I need to move to a 10 it’s gonna limit what bullets I can shoot subsonic.

I just got a new batch of 8 twist blanks if you want me to make you a 308 barrel.

 

[clowdis]

I think you may be borderline. I have a 9 twist that shoots the 200 gr. Sierra great but will not shoot 155's. However, you don't know until you try.

 

[2644ever]

Let me share my humble experience here. At the beginning of this century I attended a refresher course for the marksmanship unit of the best swat team in my country (and probably in Europe).
Not too crazy at the idea of carrying all day the boat anchor issued by the unit (A.I. AWM in .338 LM) I was allowed to bring my own stuff, a frankenstein type of a rifle hastily assembled with various parts:

 

[2644ever]

Choate Sniper stock, Savage 110 receiver (long action, formerly in .270 Win), 20" Lothar Walther, 1~8" twist pre fit barrel for Savage action, initially chambered in .300 Whisper (!) and rechambered by myself with a .308 Win Manson reamer with the help of Manson's GO gauge, BR-T8 silencer, regular Harris bipod and SWFA SS-10X scope on a 20 MoA rail.

 

[2644ever]

With this outfit I shot various types of ammo issued by the unit. From 0 to 400m, SFM 147 grs fmjbt fodder pulled from belts (the AN-F1 machine gun), from 400 to 800 meters, Lapua HPS 170 grs LockBase (very fast and quite accurate)

 

[2644ever]

and from 800 to 1,000 meters, Lapua 185 grs LockBase (extremely accurate) stuff that had been resting for so long in the armory that there was no bar code on the boxes! Those 20 round boxes were stocked in metal cans, russian style, and you needed your leatherman to open them.
That rifle worked flawlessly under all conditions and was as accurate as my buddies' big guns.

 

[2644ever]

At no time was the fast twist an obstacle, that barrel could digest all bullet weights with equally good results. Of course, if I had chambered that barrel in .300 Win Mag, the outcome might have been different.

 

[2644ever]

I also tried the subsonic ammo from Lapua (200 grs FMJ D-46 or maybe LockBase) issued for the unit's A.I. suppressed rifle, along with a few handloads that involved the costly .240 grs Sierra Matchking, again without any problem.
The real advantage of the fast twist is the possibility of successfully using medium heavy high BC bullets that would be borderline with a 10" or a 12" twist.
Have confidence... and fun!

 

[2644ever]

I am the third one from left in the line up.
Sorry for the multi part of my message, it wouldn't clear otherwise.