You may want to try increasing your powder charge in, say 0.2 gr. increases.
Remember, even if those loads shoot bug-hole size groups in other rifles, that doesn't mean ca-ca in another. Each barrel is a law unto itself.
Also, as mentioned, when your rifle is set up on its bi-pod, can you still slip a playing card all along the barrel inletting?
If you can, then try this: coat the barrel below the stock with a black / blue [colour does not matter; just that it contrasts with your stock colour] permanent marker. Then shoot a group. Remove the stock. If there is any black marks on the stock, or it is worn off the barrel, you have your answer; stock flex. What I used to do for this was buy some redi-rod; dremel out the bedding until you can fit 2 pieces of redi-rod in a V [narrow end of V is at the fore-end] in the barrel channel NOT touching the barrel. Now epoxy that in. Voila, no more stock flex.
Finally, what is the round count in the barrel? Even if it is relatively low, was it shot too fast [HEAT!] at some point to shoot the throat out?
I presume the crown is good?
Is the threaded muzzle protector tight? Have you tried removing it to see if that makes a difference?
How clean / fouled is your barrel?
I presume the brass is all 1 brand, & perhaps 1 lot?
What neck tension [on your brass] are you running?
Have you cleaned your bolt? When you do, remove the spring & roll it on the bench. If it is "wonky" [scientific term for bent! ;-) ] that could be your problem.
Remember, even if those loads shoot bug-hole size groups in other rifles, that doesn't mean ca-ca in another. Each barrel is a law unto itself.
Also, as mentioned, when your rifle is set up on its bi-pod, can you still slip a playing card all along the barrel inletting?
If you can, then try this: coat the barrel below the stock with a black / blue [colour does not matter; just that it contrasts with your stock colour] permanent marker. Then shoot a group. Remove the stock. If there is any black marks on the stock, or it is worn off the barrel, you have your answer; stock flex. What I used to do for this was buy some redi-rod; dremel out the bedding until you can fit 2 pieces of redi-rod in a V [narrow end of V is at the fore-end] in the barrel channel NOT touching the barrel. Now epoxy that in. Voila, no more stock flex.
Finally, what is the round count in the barrel? Even if it is relatively low, was it shot too fast [HEAT!] at some point to shoot the throat out?
I presume the crown is good?
Is the threaded muzzle protector tight? Have you tried removing it to see if that makes a difference?
How clean / fouled is your barrel?
I presume the brass is all 1 brand, & perhaps 1 lot?
What neck tension [on your brass] are you running?
Have you cleaned your bolt? When you do, remove the spring & roll it on the bench. If it is "wonky" [scientific term for bent! ;-) ] that could be your problem.