Keep the MK10 and don't go with the MKIII. Have read a lot of threads on Rimfire Central about annoying problems with the MK III. A long time ago I had a MK II 10" barrel and like a dummy traded it. I finally found another two years ago and picked it up. It is by far the most accurate .22 pistol I have shot. I won't make the same mistake like before. This one is a keeper to be passed down to one of the daughter's or possibly the grandson.