what keeps AR hammer pin in place?

[HankC]

Just put a Lower Part Kit in my lower. Kind of wonder what locks the hammer pin in place in AR. AK uses the spring hook and FAL has locking plate, AR trigger pin has the hammer spring leg over the groove. Don't really see any locking feature for the hammer pin. Does the hammer pin stay in place by the hammer spring force itself?

[Celtic warrior]

Hank: It should stay put once installed, note I said "should"

I've had that pin do a walkout on me a couple times, accordingly I just asked the guys here about the anti-walk out pin(s) that I have seen. I was informed that Brownell's Carries the set of two for about $10 +shipping,
which is well worth it.

I am presently waiting on a set:wink:

Greg O

[ftierson]

In the M16, the disconnector rides in a groove in the hammer pin and prevents the hammer pin from moving left to right (or vice versa)...

In the AR-15, the disconnector is shorter and does not extend far enough to ride in the groove in the hammer pin and retain it. Instead, the AR-15 hammer has a wire staked in it, one end of which protrudes slightly into the hole for the hammer pin and retains the hammer pin...

Forrest

[TheOtherChris]

If you look closely at the hammer, you should see a steel wire that goes into the bottom, intersects the outside edge of the pin hole (you can see it if you look through the pin hole) and up where it is staked to prevent it from falling out.

This wire is in the center of the outside edge of the pin hole and acts as a detent in the center groove of the hammer pin and THAT'S what is supposed to prevent the hammer pin from walking out.

The trigger pin has a similar arrangement, only the detent is one of the hammer spring legs that rests in a groove on the hammer pin just inside the receiver. That is why the trigger pin hole is relieved on each side of the trigger.

I've seen them walk out anyway, especially under FA fire.
I use anti-walk pins on mine.

[rob1]

Hammer has a "J-hook" inside it, much like an internal spring. This j-hook locks into the middle cut on the hammer pin, holding it in place, unless something is worn.