22 and 6 CM twist rates

[Muley Madness]

My 8 twist 22 creed shoots the 88gr ELD very good, and my 8 twist 6 creed shoots the 108 ELD very good as well. Depending on your elevation, I would do a 8 twist on both, but I am at 6000' if you are at a lower elevation you may need to go down to a 7.5twist

 

[Coldfinger]

Hello all,
I'm currently looking at 2 custom builds. I have 3 actions (Kelbly Atlas Lite, Mack Brothers EVO and a Defiance Guardian) that I'm looking to build into a 22 CM and 6 CM. Still trying to decide on which action for what. My question is around barrel twist rate. Am I safer for both to do an 8 twist barrel rather than 7.5? I am looking at doing 22 or 24 inch CF barrels on both. With the 22 I am wanting to shoot up in the 80-90 grain range bullet but it would be nice to have a little flex with something in the 60 range if I wanted to. For the 6 I would look to be in that 110 grain range. Any insight is appreciated. Thanks!

I've had a few 22 creeds and 6 creeds. If you're looking to send 60 grain bullets in the 22 a 7 twist will shred them within feet of the muzzle unless you run copper mono's I still have a 7 twist barrel and sold one they really shine with 85.5-95 cup&cores. I still have 2 22 creeds wearing 8 twist and have shot 85.5 down to 69 grain cup&core bullets and have had no issues up to primer popping pressures with Peterson brass.
My 6 creeds had 8&7.5 C/F twists. The 8 twist liked 95 SMK's for tack driving it was picky with bullets tho, (Remage prefit carbon six) my current 6 has 7.5 twist proof. It shoots everything from 64 grain Berger column bullets up to 105 VLD's fantastic. If I took the time on every bullet in between I know it would be a bugholer with everything it was fed.
Rest assured that you're going to run into serious problems trying to figure out which one you like better!!!! In my area there's no discernible difference out to our 300 yard on game shots to favor one over the other. My 6 creed did impress me at 500 yards on steel with a couple 1" groups but I never took 22 creeds plate punching either. Good luck!!!!!!!

 

[Weaver93]

I run 6.5 in the .22 CM and 7 in the 6mm CM, but I only run 90 and 95 gr SMKs in the .22 and 110 SMKs in the 6mm. I did run a few 88 gr ELD-Ms out of the .22 without failure, but I don't push real hard on any of them. If you are looking for a larger bullet selection I would say 7 to 7.5 in both would work.

 

[JuddL]

The current trend is to run faster twist than necessary.

I run 8's in both of mine but I shoot 80.5's and 105 hybrids. As Zen Archery said, figure out exactly which bullets and determine the twist needed.

 

[bsnyder]

Not with copper monos.

Good catch. Forgot to mention them.

 

[Hugnot]

Bullets can fly apart when subjected to large centrifugal forces, like bang - zip - puff vs. bang - zip - splat.
Just guessing the limit might be about 325,000 rpm for thin jacket, lead core bullets. Any feedback on that number?

7 twist for a 6mm CM might be excessive except for 112 grain bullets:

 

[stovepipe]

I have 2 22 Creedmoors 1/7 and 1/7.5 never lost a berger or eld in either

 

[Hugnot]

Sir Alfred George Greenhill, an old time Brit math wizard, played around with twist rates before the Miller twist rate estimator. Some people continue to use the Greenhill method.

Both are compared using a 6mm 112 grain bullet att 2900 fps:



A interesting historical note - an 8 twist, 6mm barrel shooting a 112 grain, 1.331 inch long, bullet at 2900 fps for a Sg of 1.29 might provide good groups but be "marginally stable". The good groups would support the Greenhill method until a major environmental change.

Don't order a barrel of bullets until things are figured out.

 

[GunBus]

Thanks for all the input. Think I'll try tracking down some 7.5 twist barrels. Appreciate it.

 

[DMack]

I just bought an 8 twist for a 6 CM build. Enough to stabilize a Barnes 95 gr LRX?

 

[JuddL]

LRX - Barnes Bullets

www.barnesbullets.com

Barnes says 8 will work.

 

[Lapua904]

I'm in Florida I run 7 on my 22 Creed and 7.5 on my 6 Arc

Creed runs 75's and 88's no problem and Arc runs 105's exceptionally well