I plan to shoot 120 gr to 140 gr bullets from a rifle I'm building in 6.5 x 55. Seems that most barrel makers recommend a 1:8 twist for bullet weights of 140+ grs. Would the faster twist rate affect accuracy when shooting a lighter bullet of say, 120 grs? I'd be curious to hear of others experiences. Thanks!

For target shooting and birds in top of trees 120gr is a common bullet weight wtih standard 1:8 twist. Even varmint bullets(85-100gr) shoot good enough.

I had shoot lots of birds (top of trees) by 6,5x284 with border barrels 9" twist barrel. I had use mainly lapua 9g and sierra 140gr and 142gr bullets. And accuracy was excellent. Velocity was about 890m/s so its little higher what you get whit those bullets but i dont see any problem to use it. And i think 9" twist is even better fot those lighter bullets.

But i have also 6,5mm Grendel with 6,5" twist barrel and its work also great whit 100gr and 120gr bullets so i think its yours opinion what you want.

quote:

Originally posted by LRx:
I plan to shoot 120 gr to 140 gr bullets from a rifle I'm building in 6.5 x 55. Seems that most barrel makers recommend a 1:8 twist for bullet weights of 140+ grs. Would the faster twist rate affect accuracy when shooting a lighter bullet of say, 120 grs? I'd be curious to hear of others experiences. Thanks!

When I had my 6.5 swede built the gunsmith asked what weight bullet I'd be shooting? Not being too sure, we agreed on 125 gr bullets, and he installed a 1:9 twist Shilen barrel. When I started shooting 140 gr Bergers in it, accuracy went downhill. I eventually had a Bartlein barrel installed in a 1:8 twist and have had great results, and it shoots the lighter bullets with the same accuracy.

Me, I would use an 8" twist. The trend is toward longer bullets which the 8" will better stabilize. It will also shoot 120's just fine. Same cannot always be said of the 9" twist though when it comes to longer 130's & 140's.

All 5 of my 6.5 rifles carry a 1:9 twist except one, the 6.5-284. That one is a 1:8, only because Jim Kobe talked me into it. In the others, I have great accuracy with everything including the 142 SMK.

For what it's worth, I have a 96 Swede with the factory barrel(1-8.5) I believe and it shoots 120gr. Sierra spitzers real well. I was told they would'nt stabilize in that twist, but they do.

Stepchild

quote:

Originally posted by z1r:
Me, I would use an 8" twist. The trend is toward longer bullets which the 8" will better stabilize. It will also shoot 120's just fine. Same cannot always be said of the 9" twist though when it comes to longer 130's & 140's.

Mike I like that video clip in your post, I could watch that awhile....

quote:

Originally posted by Snellstrom:
Mike I like that video clip in your post, I could watch that awhile....

Another good reason that high capacity magazines shouldn't be banned.

Thanks for the input. Sounds like I'll hedge my bets and go with the 1:8".

The vids were nice too...

I did a lot of research on this topic - 1:8 was the consistent answer.

I went with a 1 in 8.5" twist.
I haven't worked with it enough to know if thats a good choice or not. I hope it shoots 120's and 130's well but I have everything on the shelf from 100 grains to 142's just in case.