grouping issues

clem81

Well-Known Member
Joined
Apr 4, 2009
Messages
223
Location
newark ny
i have a new 243AI, that i have broke the barrel in, it is a 1-8 benchmark. and i am shooting Sierra 85 Gameking, and 90gr Bergers and 80 gr Sierra Flatbase. 44-45 gr 4350. the issue is in a 4 -5 shot groups ill put 3 on top of each other and 1 or 2 will be out 1/2 in or more. i have tried differnet depths with bullet seating. i have checked the bullet rounout .002 nmax. Now my thoughts are it is very short throuted. so i am thinking it needs to be longer so it starts into the rifling better. Is it possible the buleets base is being effected because its so far in the case. Any thoughts
 

Lefty7mmstw

Well-Known Member
Joined
May 13, 2012
Messages
4,714
Location
Dakota del norte
I'd have the throat lengthened a bit so you can get 100 grain+ bullets at the base of the neck without jamming into the rifling. 8" twist is dang fast for sub 100 grain pills in the 243 or 243 ai. That said, have you tried a bit faster powder?? I've seen 243's really shoot well with vit 540 or I4064 and 100 grain pills. You won't loose that much velocity either.
 
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