D.Camilleri
Well-Known Member
Rifle in question is a custom 338 RUM, Broughton 5C 9.3 twist, 27 inches, blue printed action, jewel trigger set to 1 lb,old style firing pin and shroud, sako extractor, bell and carlson alaskan stock with full length pillar bedding, muzzle brake. Gun was built by Cloud Peak Gun Works in Wyoming and he did a great job. I have approximately 500 rounds down the barrel.
This is really bugging me. Got up in the middle of the night and pulled the action from the stock. About a month ago I bedded the recoil lug with devcon and also bedded the first two inches of the barrel in an effort to see if it would change my cold bore poi. I looked at the mounting, made sure the magazine box was not in a bind, retorqued the action screws and checked to make sure the barrel is free floated. All last year, I would shoot to distance of 700+ yards and before I left the range I would dial back to 100 to verify my zero. I would leave with a bullseye and upon returning on a different day the first shot or two would hit about 1 moa high. I started with a cold bore shot to 700 and would hit 7+ inches high. I would back off to 100 yards and sure enough, 1 inch high at 100. I would readjust my zero and then after warming the barrel up the group would mover an inch lower. I killed a great mule deer last year at just under 500 yards and the shot hit about 5 inches higher than my aim point. I finally sent my Sightron SIII back to Sightron who gave it a clean bill of health. I am waiting for the scope to show back up and right now I have a 6.5-20 VXIII that I stole off of my 300 rum.
I have read about making notes about where your cold bore shot hits. It seems that after I deep cleaned my barrel that it now needs more fouling shots to settle in. I put about 16 shots down the tube yesterday and put the gun away dirty. The groups were getting better with the more shots down the tube, but did it have anything to do with the barrel temp rising to a stable level?
All last year the poi change was 1 moa. Now that I have deep cleaned the barrel, my first shots yesterday were over 5 inches high for at least the first 4 shots on a clean bore. I dialed my turret down 3 moa and hit several shots an inch above the bullseye. As I continued shooting my group continued to drop until finally settling around 1.5 inches low. The funny thing is that my go to Berger 300 grain load was shooting a pattern and my new load of 101 grs of rl33 was grouping fairly well.
So the big question is do I keep shooting without cleaning and see how my groups go or is there something else that I should try. I have thought about seating my bullets out longer and seeing if there is a difference. When I looked at my bore through the bore scope, the throat seemed to look good and I didn't see any eroded rifling, but then I am not an expert at looking at that.
I have taken every precaution on my handloads and they are as good as I know how to make them. My standard deviation with the rl33 loads were very low at around 8 though my magneto speed.
Is there anything else mechanical that I should look at?
This is really bugging me. Got up in the middle of the night and pulled the action from the stock. About a month ago I bedded the recoil lug with devcon and also bedded the first two inches of the barrel in an effort to see if it would change my cold bore poi. I looked at the mounting, made sure the magazine box was not in a bind, retorqued the action screws and checked to make sure the barrel is free floated. All last year, I would shoot to distance of 700+ yards and before I left the range I would dial back to 100 to verify my zero. I would leave with a bullseye and upon returning on a different day the first shot or two would hit about 1 moa high. I started with a cold bore shot to 700 and would hit 7+ inches high. I would back off to 100 yards and sure enough, 1 inch high at 100. I would readjust my zero and then after warming the barrel up the group would mover an inch lower. I killed a great mule deer last year at just under 500 yards and the shot hit about 5 inches higher than my aim point. I finally sent my Sightron SIII back to Sightron who gave it a clean bill of health. I am waiting for the scope to show back up and right now I have a 6.5-20 VXIII that I stole off of my 300 rum.
I have read about making notes about where your cold bore shot hits. It seems that after I deep cleaned my barrel that it now needs more fouling shots to settle in. I put about 16 shots down the tube yesterday and put the gun away dirty. The groups were getting better with the more shots down the tube, but did it have anything to do with the barrel temp rising to a stable level?
All last year the poi change was 1 moa. Now that I have deep cleaned the barrel, my first shots yesterday were over 5 inches high for at least the first 4 shots on a clean bore. I dialed my turret down 3 moa and hit several shots an inch above the bullseye. As I continued shooting my group continued to drop until finally settling around 1.5 inches low. The funny thing is that my go to Berger 300 grain load was shooting a pattern and my new load of 101 grs of rl33 was grouping fairly well.
So the big question is do I keep shooting without cleaning and see how my groups go or is there something else that I should try. I have thought about seating my bullets out longer and seeing if there is a difference. When I looked at my bore through the bore scope, the throat seemed to look good and I didn't see any eroded rifling, but then I am not an expert at looking at that.
I have taken every precaution on my handloads and they are as good as I know how to make them. My standard deviation with the rl33 loads were very low at around 8 though my magneto speed.
Is there anything else mechanical that I should look at?
