While I was putting my two S.A. Mil-Specs back together after they were refinished I found an interesting problem. I sent them in as pieces and that is how I got them back. After putting guns back together, even after cleaning them, I am very good about checking the safety functions of the gun. When checking these two out I found one was perfect in function but the second one would unlock the thumb safety and drop the hammer if you pulled the trigger just slightly harder than it would take to trip it normally. I obviously mixed up the two thumb safeties because when I switched the two safeties both guns were good during the function tests. Now, can you imagine if I had not checked these guns out before putting them back into service? So far I have shot 400 rounds out of each gun and they are good to go as they were before being refinished. Both of these guns have the same internal parts put in, hammer, sear, spring, thumb safeties, ect, ect. And yet there was a difference. Always good to check a guns functions and safeties after putting them back together.