I guess the phrase ...better late than never... fits here real well, but I can attest that while I had my unmodified Mac 10 (an Ingram) I was at my wits end and thought I had found what probably was to be the most expensive anchor... until I saw a bud with a "funny looking" Mac that ran like a loud sewing machine. I inquired and he directed me to Sam at Practical Solutions and after Sam worked his magic, not only stove pipes and jams became a non existence, but I could now use 9mm as well as 45's and 22's. I can now rely on my Mac-Uzi without any hesitation and what was about to be s-canned became a nice, reliable weapon. I cannot sing the praises for Sam loudly enough, and would recommend him to anyone with Mac 10 problems.