BluesBear, did you try the "old-style" (push-pin release) cylinder pin or the newer (pull-downward-rotate 90 degrees release) style? The newer style was designed to prevent the occasional "release during firing" experienced by the BW (but not the other NAA models, apparently . . .). I'm not sure, but suspect the greater mass of the BW / MM pin was a factor, and the additional barrel length of the MM may have prevented the problem in that model. Anyway, the newer style is simple & easy to release.
My BW "locked up" recently (bolt refused to drop when attempting to cock hammer, preventing cylinder rotation). I thought I'd have to send it back to NAA, but cleaned it thoroughly with spray cleaner (twice) and re-lubed with CLP. After the second cleaning/lubing, I've cycled it a couple hundred times and it works flawlessly. It was fairly new, and I suspect a tiny burr or metal filing gummed up the works, somehow.
I carry mine when my 642 is a tad too bulky (rare, actually), and find it a fast, accurate arm out to 15 yards. Power-wise, well, it's still just a .22 !