Moose milk ?
I guess the question I should have asked a long time ago is, "do your patches stick in a clean barrel too, or only a fouled one" ?
So, we seem to have ruled out all the equipment issues (yet I'm still suspect of the patch size ) that leaves your technique as the possible problem.
Technique is one of the things I changed. to solve my issue.
Try using M.A.P. instead of moose milk and swab the barrel in sections.
I squirt a little MAP down the barrel first, then swab. The key though is to swab in sections. Those little patches fill up with fouling quickly. As you near the bottom of the barrel, advance and retreat in short increments. This prevents the patch from sticking.