heck I hade a 308 that was still shooting great at 250 rounds. I told my self I would clean it when accuracy dropped off. I could not stand it at the 250 mark and broke down and cleaned.
Another side not..I had a 7rm that shot .75moa most days, some better some worse. I then got into f-class shooting and reading about this terrible thing called copper fouling. I scrubbed that barrel tell there was no copper left. It took many days of soaking with Wipeout. I was so excited to go to the range and shoot the best groups ever! Wrong!! went to a 2 moa gun. I fought it with loads again tell one day I was so pissed I sent down roughly 20 rounds in about 30 min. Talk about hot.
At about 15 the thing started grouping up. at 20-25 it was right back to a .75 moa with a smoking hot barrel. Never cleaned again and still shoots .75
I will say from my experence, factory tubes shoot better dirty and custom shoot better clean.
Sorry for the rambling.