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View Full Version : 308 twist rate and heavy subs



greyling22
11-16-2017, 11:18 PM
I'm looking g at picking up a hunting rifle in 308. The gun I'm looking at has a 1:12 twist. I know i can make it shoot with 150-170s no problem, I'm already loading lead for 30 carb, 300aac and 30/30.

But wheat if a screw a can on the end and want subsonic rounds? I know something faster like 1:10 is better for shooting 200+gen bullets, but do you think I could get something that would stabilize and be reasonably accurate in the 150-170 grn weight range?

(I'm looking at the Thompson dimension. It's oh-so funky looking, but feels oh-so good in the hand.)

Outpost75
11-16-2017, 11:24 PM
The 1:12 will stabilize flatbased bullets up to about 180 grs. subsonic. A 1:10 will stabilize #311299 subsonic.

greyling22
11-17-2017, 12:30 AM
I can live with 180grn max. I mean, 220 would be better, but the tin can won't know what hit it. And I'm not huning anything larger than a rabbit with subsonics.

runfiverun
11-17-2017, 06:59 PM
the 311359 [120grs] at 950 is more than enough bunny killer.
at least it is in my 300.

Ed_Shot
11-17-2017, 08:17 PM
Very interested in this. Have not gotten very far with gallery load development for my HOWA .308 (1-12 twist) but my NOE 311299 sized .310 with 2500+ and a coat of White Label Xlox , no gas check, over Red Dot 6.0 gr would probably jump in one hole at 50 yds if I was a better shot. The weapon definitely likes .310 over .309 or .311. The Lee 309-150-F dressed the same over Red Dot 5.0 gr. is almost as good. Conversely, I've given up on the Lee 309-113-F and 311-93-1R "for now" as gallery loads. With Bullseye or Red Dot 3.0 gr to 4.0 gr sized .309 ~ .311 with 2500+ and a coat of Xlox I've shot over 100 rd's and get 8" groups at 50 yds. My 309-113-F performs just fine with 2400 16.0 gr in this .308 and 30-06 and 30-30.... go figure. I cannot get the 311-93-1R to shoot well in anything. It drops at 90 gr. and .313.

Forgot to mention that in the 100 ea .308 cases I've set aside for gallery loads the flash holes are enlarged with a #29 bit.

jaysouth
11-17-2017, 10:20 PM
My Vanguard (howa) .308 is 1:12. It shoots Lee 309-200 into 2 MOA over 16 grs. of 2400. I lube with BLL 3x and have modded my mold to drop .310.

Larry Gibson
11-18-2017, 10:04 AM
The 12" twist will stabilize a 311299 down to 800 - 850 fps. Not only computed via the Miller Formula but have been there and done that. The 12" twist is an excellent choice for a factory built cast bullet rifle. It will also stabilize jacketed at jacketed velocities up through 200 gr RNs.