308 Palma Barrel Twist

[257Roberts]

Curious what guys are running for barrel twist in their 308 match rifles these days?
Have a palma gun I bought second hand. I believe it has some barrel life left, but I don't know exactly what the twist is.
Planning to order a barrel soon to have one on hand and ready when I need it.

The old rule was around 1:12-13 for the 155gr bullet class.

I am not sure if like a 175gr SMK will stabilize in a 1:12? Might take 1:11.

And I assume 1:10 is really only for the big stuff, 190-210gr

I think the bulk of my shooting will be 175s followed by 155s [wont be making the palma team any time soon], so I am thinking maybe 1:11. Just trying to verify if I am on the right track.

 

[DR_2297]

I like 11 & 12 for the latest and greatest 155s. My current rifle has an 11 twist because that is what was available when I was barrel shopping. Can’t complain about its performance.

 

[Steve Blair]

I have a 26" .308 with a Palma '95 chamber. It's a 10" twist and shoots 155.5 Berger Fullbore unreasonably well. Modern, quality bullets, like Berger, do not suffer from spinning a little fast.

 

[rijndael]

1:10 is my preferred .308 twist. I shoot 155-195s.

 

[Ned Ludd]

Go with a twist rate that will just effectively stabilize the heaviest (longest) bullet you think you might try. Berger's twist rate calculator is a good reference tool for making these types of estimates:

https://bergerbullets.com/twist-rate-calculator/.

Over-spinning a lighter (shorter) bullet slightly is rarely a problem, whereas under-spinning a heavier (longer) bullet can cause an effective loss of intrinsic BC, as well as stability issues if the twist rate is too low. A 1:11-twist works well with Berger's 200.20X bullet, and will also cover 155s, no problem. If you might want to try bullets such as Berger's 208s or 215s (i.e. 200+ gr bullets), a 1:10-twist would be the better choice.

 

[Rtheurer]

Curious what guys are running for barrel twist in their 308 match rifles these days?
Have a palma gun I bought second hand. I believe it has some barrel life left, but I don't know exactly what the twist is.
Planning to order a barrel soon to have one on hand and ready when I need it.

The old rule was around 1:12-13 for the 155gr bullet class.

I am not sure if like a 175gr SMK will stabilize in a 1:12? Might take 1:11.

And I assume 1:10 is really only for the big stuff, 190-210gr

I think the bulk of my shooting will be 175s followed by 155s [wont be making the palma team any time soon], so I am thinking maybe 1:11. Just trying to verify if I am on the right track.

You won't be hurt by running a 1:10 with any bullet you feel you can handle from a Sling, shooting glove and shooting jacket ( Remember this is not off a rest or bipod, recoil directly to your hand and shoulder) to shoot Palma category. 1:10 will shoot 155's all day long. ( My #1 gun is 1;10.5 My #2 is a 1:12)
The current High BC crop of 155's are really hard to beat if you look at Ballistics. I believe you need to jump up to the 185gr Hybrid class of bullets, to get any meaningful advantage over a new High BC 155 bullet going 3020 to 3050fps. Much less some of use are running 3100fps with 155's. Anything over 185's dont feel very good with your left hand Jammed up against that hand stop.
YOu can measure your current barrel twist rate with a tight Patch. When the cleaning rod makes one full revelation, if its gone 12" its 1:12. if its gone 13" well guess what? its a 1:13
I believe the old 175 SMK to now be outclassed by current 155 grain class bullets. (Just my opinion however. )
You didn't mention it, but i Presume you have a 30" barrel like all other Palma Rifle Shooters?
Best of luck to you and thank you for taking the plunge. We will be happy to have you on the line.

 

[jr600yd]

My Palma rifle has a 1/12 and shoots everything up to and including 190SMK’s

 

[Mr. Ten-X]

Curious what guys are running for barrel twist in their 308 match rifles these days?
Have a palma gun I bought second hand. I believe it has some barrel life left, but I don't know exactly what the twist is.
Planning to order a barrel soon to have one on hand and ready when I need it.

The old rule was around 1:12-13 for the 155gr bullet class.

I am not sure if like a 175gr SMK will stabilize in a 1:12? Might take 1:11.

And I assume 1:10 is really only for the big stuff, 190-210gr

I think the bulk of my shooting will be 175s followed by 155s [wont be making the palma team any time soon], so I am thinking maybe 1:11. Just trying to verify if I am on the right track.

A 1:12 will stabilize any projectile that you would likely want to shoot.

Bore dimensions of .3075 or .3080 over .2980 in a cut-rifled barrel seems to work pretty well.

 

[Kurz]

257Roberts,

This is the answer to your question without getting into all the vagaries of bullet diameters and interior land and groove dimensions. That is handled below this answer. However...

Go with a twist rate that will just effectively stabilize the heaviest (longest) bullet you think you might try. Berger's twist rate calculator is a good reference tool for making these types of estimates:

https://bergerbullets.com/twist-rate-calculator/.

Over-spinning a lighter (shorter) bullet slightly is rarely a problem, whereas under-spinning a heavier (longer) bullet can cause an effective loss of intrinsic BC, as well as stability issues if the twist rate is too low. A 1:11-twist works well with Berger's 200.20X bullet, and will also cover 155s, no problem. If you might want to try bullets such as Berger's 208s or 215s (i.e. 200+ gr bullets), a 1:10-twist would be the better choice.

I encourage you to assess your barrel condition in order to be better prepared for ordering sooner. Bartlein has already posted here that they are experiencing higher order volume which has lead times lengthening. I'm sure that every other barrel maker is just as far behind, requiring longer lead times. Plan ahead.

You may find some barrels available through online suppliers but if you require a twist rate other than what might be a standard, ordering is your only alternative.

Enjoy!

 

[r bose]

10 is what at I like

 

[Stan Taylor]

90% of my customers that buy for 308 Winchester buys a 10 twist so here ya go.

 

[jr600yd]

10 twist is great but to tell you the truth my 12 twist preforms just as good with the bullets I shoot. 155’s - 190’s

 

[Doug Beach]

Is there any evidence that a tighter bore shoots match grade projectiles better than a .300-.308?

 

[clowdis]

Probably 90% of the US Palma team and USNRT are using 12 twist barrels for shooting the 155 gr. bullets whether Bergers or Sierras.

 

[6fatrat]

1/10 would be my first choice, 1/10 would be 2nd choice.
Steve Bair