Re: Need Help on Primer Selection for Competitive .223 shooting
CCI makes a match primer that I believe is just as hot as the small rifle mag primers, but is suppossed to be more consistent. Most of the guys here that use the 223 prone at 600 are shooting 69gr up to 80gr Sierra matchkings behind some amount of Hodgedon's Varget powder. Recipies will vary, but this is generally what I have seen. The 1 in 9 barrels may not stabalize the 80 gr matchkings very well.
Hope this helps