Twist rate

[Quackaddict]

Hey guys, I have access to Shilen 243 (AI or not) with a 1 in 8 twist that I can buy right now if I want. I want to run the light bullets, 55's to 70's and push em fast. Would I loose out on accuracy by going with such a tight twist? I will order a barrel if there will be a huge difference but I haven't read one way or the other if this is a bad thing.

Thoughts?

 

[kjcpoint]

1in12 would be much better that range of bullets.

kyle

 

[fullersson]

According to Berger for those weight bullets you would want a 13 or 14 twist. Some people don't believe it but if you run light bullets in a high twist barrel at high velocities the bullet will disintegrate before impact.

 

[RJinTexas]

I've pushed 55gr NBT's close to 3800fps out of 9tw barrels in both 243 and 6mmRem and have never had a bullet fly apart, had no problems stabalizing out past 500yds. But my 6br 8tw will not group 70 or 75 grain bullets as tight as my 14tw 6br will. If the price is right and the head spacing of the barrel will work on your action I'd give it a try.

Regards
RJ

 

[DCRYDER]

I think that setup may not work very well, like fullersson said the bullets may fly apart. If i were you and if the bore looked good and was priced right i would buy it and plan on shooting heavier bullets in the 85-105 range. the 87gr v-max shoots really good out of my 8 twist Kreiger 6mmBR. You could try the 55-70 grainers for poops and giggles, never know they may work fine. But if I were dead set on shooting the 55-70s i would go with a 14-13 twist.

you say you want to push the 55-70s hard, i would think 55's would come very close to 4150fps in a 26" barrel.

food for thought: 55gr bullet+4150fps+12 twist barrel=bullet rotating 249,000 rpm.

same load through 14 twist 214,150 rpm.

same load through 8 twist is 373,500 rpm.

my thoughts and calculations, both may be wrong.

 

[LWolken]

What the others said plus if you can keep those light bullets together until impact they will sure make a mess due to rotational forces. You might be surprised shooting 87gr-105 gr bullets. The light ones blow around quite a bit on windy days but are good for one shot kills out to around 400yds

 

[sub.sonic]

Does anyone know a gunsmith that well re-chamber a 6mm-223 with a 12 twist to a 6XC? I would like to shoot 55-80gr bullets to approximately 3500+ fps. The rifle is a Savage 10FP with a small shank and I have the parts for the bolt.

Ron