If you are swabbing with a standard cleaning jag & patching materials, those are two things that could be the problem. You need to modify the jag like this. See how the lands of the jag are tapered back ?
Put the jag in a drill or drill press, turn the first land down about .010 smaller than the other 2-3 lands & then taper them so they have a sharp edge tapering back, using a small tri-corner file. This give a
arrowhead effect & the jag will let the patch push past the fouling & gather when you pull out & pull allot of the fouling with it.
Also you don't use a tight patch, you are not cleaning the barrel, you are swabbing it to keep the barrel conditions the same from shot to shot.
I use old tee shirt material as it is thin, flexible & cheap. I never use ball patching. It is too stiff & too thick & just shoves all the fouling right to the breech.
Last, if you are getting wet goop in the breech after swabbing, you are using too much liquid. Try a damp patch not a wet one. And you must adjust this as you shoot by looking at this fouling & make your swabbing solution more or less to keep it from becoming black mud. Then a dry one if necessary, but Not a tight dry one or you may end up having to shoot the jag out :shocked2:
And get ya a correct caliber breech scraper & file it as shown & about every 10-15 shots clean the breech face off & it will keep fouling from building at the corner of the breech. Notice the angled cut is Opposite the way you think, as the cut part is away from you, but when you file it is it towards you
So file it so you have to turn it to the Right (righty-tighty) to cut the fouling & thus keep the scraper screwed in to the range rod. :thumbsup: