Here are my $0.02 on the matter..
1) use the existing safety as a power switch to the RFID lock. That way, the system is not constantly draining batteries sitting idle. When the user wants to use the weapon, they flip the safety to fire position. That powers the RFID reader, which instantly reads the chip and "unlocks" or "enables" (depending on which way you want to go design wise), and then you can fire.
2) allow the user to select "fail secure" or "fail safe". In door lock terminology, fail secure means if the system fails (batteries, malfunction, etc.) the door stays locked, but fail safe means the locks open and every door is passable (safe for people who might otherwise be trapped). With weapons, "fail secure" would mean you can operate the weapon, while "fail safe" means the weapon is disabled in the event of a system failure.
3) discussing all this on a public forum will invalidate any patent rights you may want to explore.. unless you filed within 11 months of the first mention of a patentable claim.. which isn't likely to happen.. so be aware and maybe move this discussion to a private message thread if you want to retain those rights. This forum allows multiple users in a PM thread.