Help! Baffled by High Pressure Signs
I have a semi-custom 243 Win. that is built on a Rem Model 7 action. It wears a Brux fluted barrel chambered in PTG's 243 Tactical Match with a 1 in 9 twist. Action is bedded in HS stock. Leupold 4-14x40 scope.
At this point, I should probably mention that I have been reloading for 25+ years. During break in of barrel, I loaded and tried several different powders in my Lapua brass. I shot the following ladders with the 105 gr. Berger VLD:
H4831sc - 40.0 to 44.0 grains* (settled on 42.5 gr. @ 2,860 ave. fps)
H1000 - 43.0 to 46.5 grains* (settled on 45.0 gr.)
H4350 - 37.0 to 41.0 grains* (settled on 41.0 gr. @ 2,930 ave. fps)
* all loads are within min and max load range recommended by Berger
Shot drop chart w/41 gr. of H4350 - went hunting. At this point in time, I had 150 rounds down the barrel. Never fired a shot during hunt, but I did drop my rifle (not a bad drop at all). I decided to re-zero scope the following week. When I went to the range, I noticed that the same loads were now giving me a sticky bolt and some signs of pressure (cratering & extractor marks).
I started to recheck my loads wondering what was going on. All the previous loads with different powders were now showing excessive signs of pressure. I thought it might be the warmer temps, so I kept rounds in fridge/cooler prior to shooting. I double checked the weight of each charge on two different scales. I went back and checked my max COL and then backed off another .02". I reconfirmed case length was within specs. I cleaned the barrel using both BMG 50 and Wipeout to ensure there was no copper build-up. Nothing has helped.
This morning I went back to the range. I shot one round of 45.0 gr. of H1000 pulled from my cooler. I experienced serious bolt stick, with cratering and extractor mark on case along with a chrony speed of 3,021 fps (it should have been around 2,900 fps). Rather than shoot the other two, I switched to a cooled round of 38.0 gr. of H4350. This shot resulted in a stuck case where the bolt had to be pounded open with a mallet. The primer had been completely blown out of the pocket with a heavy extractor mark. The chrony showed a reading of 3,063 fps, when it should have been in the 2,750 fps range.
I am completely baffled! Where do I go from here? Is it possible that something happened to the bolt/action/barrel when it was dropped? Any ideas?