had my trigger/hammer out 3 times to tweak the springs and last night i noticed that my trigger pin was walking out. it actually walked out far enough to prevent the trigger from letting me drop the hammer. i removed the pins and re-installed to make sure they were in properly and after 25 more rounds both pins were walking again. i swapped the two pins and they were a bit better but still noted some movement.

i've got JP and KNS anti-walk pins on the way from midway.

anyone else have this minor issue?

The fact you are tweaking the springs could be the answer to your problem. The trigger pin is secured by the hammer spring.

i'm aware that it could be my fault for doing the 15min trigger job.

i was just curious if other "tweakers" are having the same issue.

When you did the 15 min. trigger job, did you follow the instructions and reverse both pins so that the retaining grooves were now on the left side of the receiver? This is a critical step to them staying in place. Mine has performed flawlessly for at least a thousand rounds.

The pins are the same part.

1. There is no way for the hammer pin to "walk out" of the center groove if the J-clip is in the hammer. Be sure the hammer pin "clicks" into the hammer when the pin in in. You can test this on the bench.

2. There is only one groove near the end of the pin. This is designed for the hammer spring leg. If you clipped the right leg of the spring you need to ensure the left leg engages the groove -- and that it's also on the left.

None of the pin retainers will work to my knowledge as their pins are too short for the thickness of the M&P15-22 receiver.

-- Chuck

My thoughts exactly.

i modified the 15 min trigger job by not cutting a leg on the hammer spring so it shouldn't matter what side the groove is on the pin.

i'll have to check if the pin clicks into position in the hammer but that is not the main issue. the trigger pin is the real walker. i'll check to make sure the hammer spring leg is engaging the groove.

anti-walk pins are already on the truck to my house so i'll find out if they fit hopefully by this weekend.

I have a set. They're not long enough. Nor are the necessary on this rifle nor the real version. Something else they make because someone will buy it!

-- Chuck

KNS pins work...there is enough hammer pin that sticks out either side to engage the connecting bar between the pins. You just have to fill the space inside the slot on the bar to keep the hammer pin in place. I used a brad nail cut to length.
I know I know flame away....it's my toy I can do whatever I want to the damn thing .


Edit: As you can see in the first and second picture, with the hammer pin centered, there is still enough sticking out to engage the retaining bars.


The problem is that the 15-22 receiver is wider than a standard ar-15 receiver.
This makes the hammer pin to short to be fully engaged once everything is installed.
All you need to do is fill the gap in the retaining bar with something solid.
I used a brad nail the same width as the slot in the retaining bar and cut to length.
This leaves enough room in the retaining bar slot for the hammer pin to engage both retaining bars and allows everything to fit snug to the side of the receiver.

Once everything is installed this will keep the hammer pin snug between the two retaining bars.

BTT for KNS pin non believers

I use the KNS pins on my standard AR-15, but they are not "really" needed unless you are shooting full auto. But even in a semi-auto, they can add a little longevity to the receiver, but it's doubtful that you will ever shoot the rifle enough to find out.

The whole point of the KNS pins is to keep the hammer pin from rotating so that it doesn't wear the receiver. The fact that it keeps them from walking out is just a side effect from the design. The grooves in the trigger pin that engage the hammer spring are more than enough to keep the pins in place. However, if you have modified the spring so that little tension rides on the trigger pin when the hammer is fully released you can expect problems. And of course, if you've clipped one side of the spring, you need to make sure the groove is on the side where the leg still exists.

thanks for all the info guys. glad i didn't alter the OE springs and have a spare set of dpms springs just in case. i also ordered a set of JB reduced power springs to see if i like them. luckily i have extra guns to use all these spare parts in.

i know i'll never shoot them enough to warrant the need for KNS pins but you know what they say about the guy who never spent any money on any toys...he died rich.

Howdy, folks:
I'm new to the forum, but I've been watching posts for some time, particularly regarding the 15-22. I think that is's true that we won't wear out our guns by pin rotation, BUT, I put KNS retainers in both my 15-22 and my SR-556 because I think the hammer and trigger sould rotate on the pin, NOT the pin rotate in the reciever. The new pins are bearly long enough of thee 15-22.

The Army has rare problems with "walking pins" and "receiver wear." But what do they know about these rifles?!

They make lots of "accessories" merely 'cuz someone will buy them. These fall into that category. It's your money...

-- Chuck