AR 15 Anti walking pins

[Keyfer 55]

When I was in the military I don't remember the M16 having anti walking pins . What's different on the AR15 s .
My hammer pin would creep out about 50 rounds on my AR15.

 

[Hokie_PhD]

I'm not an expert but I think they're mostly for drop in triggers. I think others that use them are just for tatci-cool purposes.

But I could be mistaken so if someone knows better they can correct me.

 

[earlthegoat2]

There are isolated cases of pin walk using mil spec triggers under normal use.

I heard a story about pins walking under sustained full auto fire. Maybe enlarging the trigger/hammer holes too. I believe this may be what caused them to be pioneered into the civilian possessed M-16s and not the military units. In other words, civilians who owned machine guns would put more rounds through them then the military would and then they wouldn’t maintain them properly.

Generally speaking they are a good idea for drop in triggers.

 

[Elkins45]

If your trigger pin is walking it’s most likely because the hammer spring is installed backwards. If your hammer pin is walking it’s most likely because the J spring in the hammer is weak or missing. A properly set up AR with conventional fire control parts shouldn’t need them.

I do like the ones that have the little ‘bridges’ between the pins for use in 9mm guns because the hammer pin takes a pretty good whack due to the blowback action. The bridge lets some of the force be shared with the other pin and spread across more of the receiver.

 

[bassjam]

I think it's pretty isolated cases on AR15's. I don't an issue with my M&P Sport, but my daughters M&P 15-22 had the trigger pin walk out within the first 200 rounds. It's possible something was installed incorrectly from the factory, but I went ahead and added anti walking pins to her gun just in case.

 

[Varminterror]

Cartridge style AR FCG’s require anti-walk pins. If pins are walking on a non-cartridge style, then it’s likely because the grooves in the pins were not deep enough.