When accuracy drops off is so variable from one barrel to another , one type to another , one grade to another , type of bullets used , coatings used , but here is what I found in my guns over 50 years is that enough experience for you ? In most of my barrels using uncoated jacketed bullets I could see accuracy started to go off at around 30 shots , acceptable accuracy for short range hunting would be around 50-100 shots but it's a subjective thing some are happy if the gun shoots 4 inch groups , this is a broad average over several guns . I never use monolithic bullets . If I use pure Moly coated bullets from my own process I can shoot 250 to 300 shots in my 223 before I see accuracy wondering from one test I did . Usually I would never fire that many in one go and I always clean and grease the barrel after use if storing for a while . Actually cleaned my 223 this morning just to check the barrel after three years of no use and it is perfect , grease was dry in the bore but the metal surface was sealed well . No adverse effect from the moly that I could detect because it has been lightly cleaned to remove excess surface moly that can harbor residues ( most important in a CM barrel ) and properly lubricated before putting away in a safe that has silical gel moisture traps . Carbon and copper lay down as layers in the bore of the barrel and inter bond so if you are nor cleaning both you are not cleaning period . Go to a BR range and you will see them cleaning fairly often using uncoated bullets because they can see the accuracy going after a few groups .
