I've been checked by 2 different USFWS wardens with a matchsaverz on my gun. No ticket. matchsaverz does not alter the capacity of the magazine, and still requires manually loading the round. Federal regulations do not state "magazine" or "chamber" specifically when referring to guns not capable of holding more than 3 rounds, but there are a few places on the USFWS website that say "magazine." I've got them screenshotted and saved on my home PC should I ever get a ticket.