.22 CALIBER (.224) 77 GR. HPBT MATCH CANNELURED The .22 caliber 77 grain HPBT MatchKing is a cannelured version for the civilian market. Due to the fact that the 77 grain bullet is the heaviest magazine length tolerant .22 caliber bullet Sierra makes, it is a big favorite with the AR crowd. For years many customers requested that we sell a cannelured version for civilian use. Sierra is happy to have made that a reality for them. Please Note!! This bullet requires a 1x7" to 1x8" twist barrel.