6mmAI 105 Berger - 9"twist

[AndyW]

Anyone shooting the 105 Berger out of a 6mmAI?

Will a 9 twist stabilize it?

Thanks.

 

[1000yardstare]

Shot F Class this past year with an 8 twist 6AI. Bench tested 105 AMax (non-moly), 105 Berger and 107 MKing at 300 metres last Spring. The 107 MKings averaged the tightest groups, next 105 AMax, last 105 Berger.

F Class practise and competition at 1000 yards in the Summer bore this out with the 107 MKing definitely superior, shooting the highest scores, next the 105 AMax, last the 105 Berger.

These were the results in my 30 inch MacLennon barrel. Other rifles may give different results. I am currently shooting the moly 105 AMax off a 300 metre bench. Looks about the same group sizes as the non-moly.

 

[cmillard]

it should stablize those bullets, since you will be pushing them at the speed of light with that cartridge. but you can always go one half turn extra--it should be a sure thing then--just to be on the safe side.

 

[Bugs]

You should not have a problem. . . . My 9 twist .243 Ackley stabilizes 107-107 grain bullets just fine and I only push them about 3200 or so.

 

[Yellow11]

Don't get too marginal before you looking at the maths!

105g VLD @ 2800 fps will produce a gyroscopic stability factor of 1.18, pro rata this to 3200 fps will give you a G.S. factor of 1.349.

Target minimum gyroscopic stability factor is 1.4

IMHO use a shorter 105g bullet than the VLD or a tighter twist