To echo .300Wby, I think that ammo quality is a larger factor than ammo quantity.
Growing up, I shot a lot of skeet with my dad. Enough to go from zero to "pretty good." We'd run a patch down the bbl, wipe it down with lemon oil, and put it up. It was lubed with lemon oil or WD40, depending on circumstances.
I just didn't know any better as a kid and the only repeater my dad had ever owned up to that point was a bolt-action JC Higgins.
What saved my bacon was that my dad knew a guy who could get us some really nice, clean-shooting loads cheap (wholesale). I recall disassembling it once as a kid, without the aid of a manual, and going over it in detail (but still didn't remove the trigger group). No internet download of the manual in those days.
I know better nowadays and it is my HD shotgun. I shoot it periodically, but only give it a detail cleaning once a year (replacing the O-ring at this time), as I'd rather not remove my mag ext, & tac light more often (and causing a change in POI).
After each session, I wipe it down, scrub the bbl, and clean out the receiver pretty well with swabs & pipe cleaners. I also use quality ammo, not Wally World bulk packs that seem loaded with "explosive dirt."
I doubt I'd get away with that using crap ammo. I've sen similar things with centerfire pistol ammo. Winchester white box or Wolf makes it look like I'm shooting black powder out of my 1911. Good quality stuff leave little residue.