Need Help Deciding Which Twist Rate for Cast Boolits

[Treetop]

I plan to re barrel my Savage FP-10 in .308 Win. I will be shooting 180-200 gr. cast boolits almost exclusively. I have a choice of 1:10, 1:11, or 1:12 twist rates. Which one should I buy? Thanks, Tt.

[onondaga]

1:12 is great for the lightest bullets, you are shooting the heaviest bullets in that caliber, I'd recommend the 1:10 faster twist for those.

Gary

[HARRYMPOPE]

I have shot 1-10 and 1-12 in the 308 and 30 BR and think the 1-12 is fine.The Remington 700 varmint is a 1-12 and with 180- 200g bullets a top performer.With even a 200g cast bullet the length will still be within easy stabilization even at 1600 or so.I shot a 195g NEI for many years @ 1650 and placed well in CBA matches.Any twist you mentioned would be fine.


HMP

[felix]

Gary, I am not so sure. Larry has guns with all the twists and maybe he should help here. It very well might depend on which boolit style being talked about and the throating in TT's gun. ... felix

[Larry Gibson]

The 12" twist will be best for the 180-200 gr cast bullets you mention. With the slow end of medium burning powder such 4895/Varget up through 4350/RL19/H4831Sc and perhaps RL22 in the slow burning range those bullets will do very well up into the 2100 - 2300 fps range depending on your casting and loading abilities. If you could get a 14" twist it would be better for 150 - 180 gr cast bullets.

Even if you should decide to use J bullets remember the 12" twist was the standard twist for all factory loads up through the 200 gr bullet. If you're getting a target or long range like set up then the 12" twist is also optimum for the 175 gr Sierra MK, the bullet of choice for the long range in the .308W. Works as well for cast.

Larry Gibson

[Doc Highwall]

What Larry said. The 1-10" twist is from the 30-40 Krag with 220 grain bullets.

[runfiverun]

the savage f-class rifle they just come out with is a 1-13 twist.
and most 30-30's i have ever seen are 1-12.
i just got a 1-14 twist and i am looking for a smith to cut a chamber for a case smaller than a 30-30 into it.

i'd go with the 12.
if it's a dedicated cast shooter i'd , wait i did, go slower.

[Treetop]

Thanks for your replies, guys! After reading your replies, here is some more information I guess I should have included in my OP:

1) I'll be using mostly 311322, 311291 and 311299s.

2) My favorite powders are H4895, IMR 4227, and AA 5744.

3) I will be using both gas checked and paper patched boolits.

4) The rifle will be used with cast boolits~90% of the time, the rest will be 168 or 175 grain Sierra Match Kings.

Tt.

[Bass Ackward]

No offense, but what designs and powders you like may NOT be what the new barrel wants regardless of the twist rate.

It all starts at the throat and the rifling height if you are a bore rider fan. That determines what designs can enter the bore on center and what power speed is needed to allow it to perform that task.

But Larry gave you sound advise based upon your question. I would go with a 12 twist also.

[45 2.1]

Remember this...... it is MUCH more important to get your boolit into the rifling concentrically when fired than any other item including rate of twist.

[Pat I.]

Go with the 12.

[geargnasher]

No offense, but what designs and powders you like may NOT be what the new barrel wants regardless of the twist rate. ...

My thoughts exactly. Always difficult to predict exactly what the gun will like. You might find it likes 4350 more with a certain boolit, or 3100. Hard to tell unless you try some things. Generally speaking, if one has the option for a slower twist in .30 caliber, take it.

Gear

[HARRYMPOPE]

Go with the 12.

simple answer,that was needed!

HMP

[Treetop]

Thanks guys! 1:12 it is! Tt.