300 wsm headaches

[HPBTMTCH]

Last year a friend bought an expensive rifle chambered for the 300 wsm, he brought it over and wanted a load built for his alaska hunting trip. I started with RL 22 and 168 gr. barnes triple shocks, and nosler 180 gr. accubonds, it shot these like the high dollar rifle it was, no problems. Most loads going under half MOA. This year he said it would not shoot a group under 3 inches. I thought that was a bit strange so i told him to bring it back and i would check it out. Sure enough i shot his loads and it would throw flyers all over the place. He said he lost or shot last years rounds and could not find the fired brass. He did have the same powder and lot #bullets though. I loaded 3 rounds and thought they seated with very little effort, so i checked if i could turn the bullet with my fingers and suprisingly i could. The dies are from redding but are`nt the bushing style. I measured the brass and it went 12. 5 to 13 thousanths. Thats pretty thin. Bought 100 more new brass and it measured 15 to 15.5 thousanths and figured i had the problem solved, not so. It still shot flyers. I looked at the barrel, and it was fouled bad. Ran patches for 8 hours and let it soak over night. Ran more patches and it showed rust under the copper, it`s stainless so who would have guessed. After several JB patches it looked clean. Back to shooting. Now it would bughole 2 and the 3rd would be out about 2 inches, no problem you think, right? but the 4th round would land where the 3rd went the #5 would be in the same hole and # 6 would be 2 inches farther than that, and they would walk around, never going in the same place, without moving the scope. Changed scopes, checked mounts, same. Retightened stock bolts to specs and checked bedding, nothing wrong. After many expensive componets down range could not get it and gave up. The bore looks shiny, but could the rust have changed something? Cleaning it showed no exessive copper fouling, nor does it make it shoot better. So with the hunting trip in days he buys a rem. 700 in 300 wsm, and it starts again, this thing won`t shoot either. Finally i stumble on some leftover 200 grain sierra gamekings, with win wmr primers and RL22, it shoots these into .4`s, and the 10 round group went under an inch !! But it is so picky that 3 rounds with fed 215 primers went out to 1.6 inches. Oh well, it likes one load and thats it. But it does shoot one load, me, i`m just glad it`s over, lol.