I agree with above.Check your action screws,take your scope completely off,check your bases,remount your scope and see if anything changes.When you sight your rifle back in,if adjustment don't go the way you move it,it could be a problem with your scope too.Give your barrel a good cleaning,shoot some ammo that you know shoots well in your rifle and see if any of that helps.I do bed the recoil lug on my Senderos.That aluminum bedding block does a good job at supporting the bottom of the action,but the inletting for the recoil lug can be a little sloppy for my liking.I would consider bedding the lug,it sure won't hurt.
"I am getting inconsistent performance from my rifle after each barrel cleaning (have to re-zero)."
This statement makes me suspicious that what you are seeing is normal "point of impact" (POI) movement of the bullet after cleanging. If there is oil or solvent residue left in the barrel, and there invariably always is, this will cause the first shot (or more) to fly off course. If the rifle is solid (i.e., action screws tight, barrel not touching, consistent trigger) then it should settle down and return to it original zero (or POI) after the barrel is slightly fouled. My rifles usually like at least one fouling shot and then they're back in their groove(s).
I may be way off base. You are using the same ammo each time, correct? Do you give the rifle time to "settle" down after cleaning the barrel? JohnnyK.
Yes, once I rezero it does hold until I clean the barrel. Then my zero changes (within an inch or so) and I have to adjust nightforce scope and then I can put the next 20 in 1/2 inch group.
Then the cycle starts over again. I clean the barrel. Shot 3 fouling shots, then I put the next 20 in a different place then before.
That is what makes me think it's not the scope or mounts because the only thing changing is cleaning my barrel.
The rifle used to not do this, a recent change. The only thing that changed was that I started de-burring my flash holes this last time and it shot 1.25 inch higher than before. I don't see how that can make much of a difference. I shoot handloads (60.5 g. of IMR4350, 3.345OAL, CCI Mag primer, nosler brass, 160 accubonds). All sorted and weighed. This load is proven over the past year in the gun for 1/2 inch at 100.
I have about 400 shots through the gun so I don't see how I could have shot it out. I recently had a gunsmith go through the gun too and he didn't see anything too wrong with it. He said it's not straight (action-barrel) but said that is normal for a remington.
I would likely test the security of the scope before doing anything. Shoot 4-5 rounds then hit your scope with the heel of your hand & see is zero shifts.
Assuming your action screws are torqued properly, my next thought would go to lapping your lugs. When you clean the gun you remove the bolt. If it's not stable you could see minor differences in p.o.i. — especially with the action out of line with the bore. I would suggest having the action trued, lugs lapped & recoil lug bedded.
Scopes do go bad & mounts do work lose, not often with quality parts, but it does happen. I second the suggestion you remove the scope & mount, then reinstall each.