Backstrap, had the same problem with one of my Ruger factory 10-22 clips. I filled it up with bore cleaner, let it set for about a minute, poured it out, poured it back in and let it set again....flushed with Rem Oil, turned it upside down on a rag and let it drain...works great. Not sure how old your clip is, but this is the original clip and my rifle is a walnut stock, checkered, no barrel band. I have had it 12 years and I bought it used.