How many of y'all hunt with a slightly fouled barrel or clean? I guess it depends on the rifle, but I'm wondering how much leaving a fouled barrel can affect the barrel in the long run if left for a hunting season.
I can't tell much, if any, difference, as to point of impact, with my centerfire rifles but my match barreled .22LR has given me fits.
SK Standard Plus needs to start from a clean barrel and even then the POI moves a bit until i've got 15 or 20 shots through it. Because of that, I've left the barrel fouled before heading to the woods the following weekend- that didn't work out either. I think the greasy lube on those bullets dries out in the barrel or goes rancid or something because the first groups, with week-old fouling, can move the POI an inch at 50yds.
Different .22LR ammo has it's own thing going on in my match barrel but I have found that CCI, be it their "Standard Velocity" or "Mini Mag" offerings, always shoot best with a clean barrel (in my rifle). With CCI Mini-Mags, from a clean barrel, the POI is always the same and groups are tightest, impressively so. After 20 or so shots, their groups open up- just the opposite of SK or Eley ammo. In fact, CCI "Mini-Mag" ammo's accuracy, from my rifle, blew me away! ...Especially for a supersonic non-target round. Mini-Mag's easily equaled the best groups from SK Standard Plus, but only from a clean barrel and only for about 20 shots- then I'd have to swab the bore again.