SmallCaliberCentral

Bought a new Savage mod 12 varmiter about a year ago. Bought 500 cases and began developing a load. Ended up with 40 gr V-max & 26 gr H-335 for consistent 1/2 moa groups. Went prarie dog hunting last spring and it did well. Recently started having problems with accuracy. Thought that it was my cleaning method, but found out different today. Shot the rifle this AM with a box of bullets that have new brass (RP), but same load. It shot 10 shot 1" group at 200 yds, normal. Went home for lunch, cleaned the rifle and returned to range to shoot at 300 & 400 Yds. First shot at 200 yds to check and 2 each 5 shot groups were 5" and 3.5" at 200 yds. The only difference was that the cases were once fired. I retrieved another box of bullets with new brass and they shot 1/2" moa 5 shot group. Have been full length sizing the brass with Hornady die. This will definitely make me buy a different die and probably a neck sizing die to try. I will check runout on the FL sized bullets as soon as I get back to work where I can get a dial indicator. Have been loading for almost 40 years and this has been driving me crazy. Comments and recommendations welcome.

E-Texan shooter, I've got a rcbs case master gauging tool for checking for run out after each step when reloading. I check once after a case has been fired in the gun to make sure there is no run out. If I full lenght or neck size my brass I check after each step and after seating the bullet i check it agine. Then if i get any run out i know right where it came from and i can do something about it. But here is something that some one was talking about on the fourm in a post. And i forgot who said it. But take some scotch brite pad and put a little on a doll in a drill and run it in the neck. It makes the neck nice and smooth in side. And i think it helps when seating your bullets. I hope this helps you out some. Lee