06-10-2011, 04:59 PM
Warped,
I've done a CQM range before where I literally fired over 1,100 rounds in less than two hours, and they were all on-target (FBI silhouettes). Actually, my avatar pic is of that particular range/day I'm speaking of, and one of the guys that was running it had burnt 10,000 rounds through his M4A1 the day before, after tossing his previous upper and getting the "New" one, which he took to bolt service life in one day. With all the civilian AR's, M16A1's, M16A2, M4's, and M4A1's I've burnt ammo through, I never had a slam-fire, and all my range sessions have usually been no less than 300 rounds on the civilian side. I've never had a slam-fire with a Garand, M14, M1 carbine, or M1A either.
It was more common on the early Armalite AR15's that had a larger firing pin head, which had a lot of mass to it. As they transitioned from the prototypes to the Colt Model 601 (first Colt-made military AR15 with Green painted furniture over the bakelite, chrome BCG, slickside upper/lower) and Colt Model 602 (all black, still "slickside", 1/12 rifling, no chrome bore anymore), they kept the large head firing pin, and as a result of the evaluations and incidents of slam fires with those, they went to the lighter firing pin on the XM16E1 in 1964, which is still the current design.
HK used a firing pin spring and safety plunger on the 416 & 417, but that is classic over-engineering (the plunger). I do like the firing pin spring design on the current Armalite AR10's, but in practice, the floating pins with lighter weights have not been a problem. You can also buy a Titanium firing pin, but the tips have supposedly galled on them when used in AUTO guns.
LRRPF52
I've done a CQM range before where I literally fired over 1,100 rounds in less than two hours, and they were all on-target (FBI silhouettes). Actually, my avatar pic is of that particular range/day I'm speaking of, and one of the guys that was running it had burnt 10,000 rounds through his M4A1 the day before, after tossing his previous upper and getting the "New" one, which he took to bolt service life in one day. With all the civilian AR's, M16A1's, M16A2, M4's, and M4A1's I've burnt ammo through, I never had a slam-fire, and all my range sessions have usually been no less than 300 rounds on the civilian side. I've never had a slam-fire with a Garand, M14, M1 carbine, or M1A either.
It was more common on the early Armalite AR15's that had a larger firing pin head, which had a lot of mass to it. As they transitioned from the prototypes to the Colt Model 601 (first Colt-made military AR15 with Green painted furniture over the bakelite, chrome BCG, slickside upper/lower) and Colt Model 602 (all black, still "slickside", 1/12 rifling, no chrome bore anymore), they kept the large head firing pin, and as a result of the evaluations and incidents of slam fires with those, they went to the lighter firing pin on the XM16E1 in 1964, which is still the current design.
HK used a firing pin spring and safety plunger on the 416 & 417, but that is classic over-engineering (the plunger). I do like the firing pin spring design on the current Armalite AR10's, but in practice, the floating pins with lighter weights have not been a problem. You can also buy a Titanium firing pin, but the tips have supposedly galled on them when used in AUTO guns.
LRRPF52