220 Ackley fast twist

[butler12]

Hi,
I am considering re barrelling my 1 in 14 220 Ackley and wondering which twist to get to shoot 75gr Amax and 80gr Berger VLD. I was wondering if I should go a 1 in 8 or with the extra speed of the case could I get away with a 1 in 9.

 

[Hotshot]

I have no trouble with 80gr Sierra bullets in my 9 twist. 75 A-Max have been disappointing and the Bergers shoot almost as well as the Sierra.

 

[xswanted]

Are you going to shoot in the cold?

I'd go with an 8 personally, just to be on the safe side.

 

[357Mag]

Butler -

Howdy !

For shooting 75 "A"-Max in my wildcat . 22-35Rem, I went w/ a 1-8 K & P SS 5-groove.
I shot the 75"A"-MAx exclusively, and they shot superbly for me (my gun, my loads ).


I'm wondering whether even a 1.75 might not be a good idea, to ensure you could fully exploit your case' capacity w/ the " heavies " ?


With regards,
Kevin

 

[40X Guy]

Go with the 8 twist. Then you are assured of shooting 80 grainers if you see fit. Just make sure you have the chamber throated with correct freebore for the 75-80 grain class bullets which is going to be around .075 freebore.

I have my new standard .220 Swift 8 twist build ready to go set up for 75 A-Max but weather here has not gotten over 20 degrees for a few months... :'(

Frank

 

[LCazador]

Even in my old 22/6mmAI, a 9 twist did not do a good job of stabilizing 80g. bullets. Velocity has little to do with proper stabilization. Do an 8 twist.

 

[Hotshot]

LC I have to call BS on that one! "Velocity has little to do with proper stabilization" ???
We are talking about rotational stability that is the result of the twist times the speed.
I will agree that 1:8 twist seems to fit the formula better than the 8.5 or 9 that I have seen work well for higher capacity cases.