If the problem is not rectified as per the above cleaning suggestions, inasmuch as they are "club guns", they may have high round counts. I had a S&W 58 (.41 Magnum) in which either R-P or W-W (cannot remember which) cases would stick, the other brand not being a problem. Turns out that the gun had excessive end shake and the difference between the thickness of the two different brands of rim thickness made a difference. So, if everything else fails, check for end-shake.
Sometimes you get what you pay for, sometimes you only pay more for what you get.
Three shots are not a "group"...they are a "few".
If the Bible is the literal, infallible, unerring word of God...where are all those witches I am supposed to kill? (Exodus 22:18)