Coolbox--I don't know. 80% of what I post about cleaning guns is in jest. When I have 'scoped the centerfire pistols, they just weren't very dirty, no lead and little copper. The .308 centerfire rifle was a lot worse. The .22 rifle was a .19 and didn't look good at all. The Kadet bore never looks bad, compared to the 22 rifle. The rifle bore looks ok from chamber to mid point, then there is a lead buildup from there to the muzzle.
I've never noticed much difference in the pistols after cleaning the bores. I've always noticed a difference in the rifles, especially the 22 with lead bullets.
The pistol barrels must be easier to manufacture also--they look very smooth and slick compared to the 22 rifle bore which has lots of visible chatter marks in it. This has to make a difference in how long they will go before the build up is enough to swage the bullet mid way down the barrel and loosen it up as it exits the muzzle causing the accuracy to tank.
So, bullet choice, barrel finish, etc. all must affect how long you can go. I went waaay too long on the rifles but don't know how long I can go on the pistols. I've gone several thousand on the centerfire pistols without scrubbing the bore with no loss in accuracy. I'm not sure my P-09 barrel has ever really been cleaned very well after 12k rounds.
Joe
