Lately on arfcom, there has been a heavy push towards reliabiliy upgrades, like Crane O rings, D-fenders, heavy tension extractor springs, shrouded fire pins, etc. What is the mil-spec requirement for these springs, and are these things exceeding that tension standard? I haven't heard of any problems using these various 'upgrades' (i've used a D-fender, O-ring, green Specialized Armament extractor springs--but NOT all in the same gun!), but was curious if you guys have seen/heard of any problems.