Hammer J spring broke.

[laytonj1]

After my first range session I get home to clean the gun only to have some kind of J shaped spring fall out when I removed the receiver. Everything seemed to function well so I cleaned it and put it back together. After the 2nd time at the range I discovered the hammer pin walks when I shoot it.
So, turns out the J spring in the hammer is what broke off.
I contacted S&W and they said they'll email me a call tag to ship it back.
However, I'm thinking maybe I should just replace the hammer pin with a JP anti walk pin. I noticed they are a little oversized (.156 vs .154). Have any of you tried installing these? Did they fit well or did they require reaming the hammer?

Jim

EDIT: Nevermind, I ordered the KNS anti roll pins instead.

 

[HYRYSC]

After my first range session I get home to clean the gun only to have some kind of J shaped spring fall out when I removed the receiver. Everything seemed to function well so I cleaned it and put it back together. After the 2nd time at the range I discovered the hammer pin walks when I shoot it.
So, turns out the J spring in the hammer is what broke off.
I contacted S&W and they said they'll email me a call tag to ship it back.
However, I'm thinking maybe I should just replace the hammer pin with a JP anti walk pin. I noticed they are a little oversized (.156 vs .154). Have any of you tried installing these? Did they fit well or did they require reaming the hammer?

Jim

EDIT: Nevermind, I ordered the KNS anti roll pins instead.

Good idea. I certainly wouldn't ship the entire rifle back just for that.

 

[apiccola]

The OEM pins are "anti-walk". They have a groove that the spring sits in under tension. When the spring breaks, the tension is lost, and the pin will "walk". I think you will discover that this is the case with all brands of AR trigger pins.

 

[laytonj1]

I think you will discover that this is the case with all brands of AR trigger pins.

The KNS pins are secured externally by screws. They do not need the J spring to secure them.

Jim

 

[apiccola]

oops, I should have phrased that as most ... sorry about that. That KNS Non-Rotating Pin Set is pretty nifty.

 

[apiccola]

You may want to confirm clearance for the pin retainer strap on the right side of the MP10 lower below the ambit-bolt latch. If the kit has the thicker strap, you may have to notch the strap to clear the bottom of the latch.

 

[apiccola]

Thanks for pointing these out. I picked up a set of the ST type for an AR15 build this evening.

 

[laytonj1]

You may want to confirm clearance for the pin retainer strap on the right side of the MP10 lower below the ambit-bolt latch. If the kit has the thicker strap, you may have to notch the strap to clear the bottom of the latch.

Yeah, I ordered the kit with the thicker straps. I had to notch both of them to clear the ambi's but it was a quick job with my Dremel. Otherwise, it took all of 5 minutes to install. They look good too.

Jim