Ahha the dreaded crud ring, you must be shooting 777 pellets, eh? i have the same problem with my encore when I shoot 777 pellets. I don't know if the loose 777 powder does the same or not, I have never tried the powder. I would shoot then swab with a very wet patch of half alcohol and window cleaner (the blue stuff). I would run my jag w/ patch down the barrel and when I would get close to the "CRUD" ring I would chip in to it a little at a time until I broke thought it, but, a wet patch helped alot. I would then run two or three dry patches to get the barrel really dry before I would load it again. I could load it a couple of times before I had to clean it, though. I think the accuracy suffered from the dirty Barrel, too! I got sick of swabbing that crap out of there all the time.
I finally got smart and bought some Blackhorn 209, it cost a little more, but, man it's worth it. It's clean, no swabbing between shots, that makes it worth the little extra money right there, and boy does it shoot good. 100 grains and a barnes 250 grain TMZ with a harvester crush rib sabot (yellow one) for boat tail bullets, because the TMZ is a boat tail type bullet and the crush rib loads a heck of alot easier in those tight Encore barrels than the factory sabot that comes with the Barnes. It's pretty accurate, also. I have my Encore two inches high at 75 yards, but, the grouping is like a clover leaf. Do yourself a favor and try some of that there Blackhorn stuff you'll love it, Dude.