Do you see what I see?

[jscwerve]

Well, I was taking a few pictures of my AR for a buddy, and noticed something odd while looking at the pictures. Now a KNS pin kit is on the way! I knew the pins were a bit loose when I put it together, but I didn't think they would actually move laterally.

http://i686.photobucket.com/albums/vv228/jscwerve/DSCF0450.jpg

[gcrookston]

does happen. I was shooting short bursts with a friend's M4 a while back when it just stopped working... Fiddled with it for about a minute before I noticed the hammer pin had worked out.

KNS, yes, I have them in all my ARs since that little episode...

http://i268.photobucket.com/albums/jj19/gcrookston/DSC00279.jpg

[Dr_Fwd]

Hammer and trigger pins will not walk out of a properly assembled/functioning AR.

This

[Hoser]

Hammer and trigger pins will not walk out of a properly assembled/functioning AR.

You mean should not walk out...

KNS pins are cheap insurance.

[jscwerve]

Possibly. As far as I know it is assembled properly, I went through it twice. I am all about attention to detail, expecially when dealing with firearms. What could possibly be assembled wrong that would allow it to move laterally? The hammer spring in is the proper direction and the spring end is in the groove where it is supposed to be. I am guessing crappy weak spring from the DPMS kit I used. If the spring is too weak, that could also be the cause of the failure to ignite issues I had on this guns first range trip (6 in first 100rds).

If that is the case, I will trash the DPMS stuff and go with something else.

[jscwerve]

Things to look at.

1) Shallow/missing/incorrectly cut groves on the trigger/hammer pins themselves.

2) Incorrect/damaged/missing spring pressed into the hammer

3) Improperly bent/damaged/installed hammer spring.

1 & 3 are the ones I see the most in hobbyist/homebrewed guns.

Well thanks for the advice, when I get up tomorrow I will check a few things. I am positive the hammer spring is installed correctly, I do not even see how someone could screw it up, it is pretty obvious if directions are followed and looking at the diagram. I will check the pins. from what I can remember, the grooves seemed a bit shallow. If this is the case, I am sure as hell not buying anything from DPMS ever again.

[Hoser]

No I meant what I said. If they're walking out, technically its not a properly assembled/functioning AR. Everytime I've seen a problem with a pin there has been a tolerance/assembly issue.

Dont forget that shit happens and there is always Murphy.

[jscwerve]

http://i686.photobucket.com/albums/vv228/jscwerve/eating_crow.jpg

MMMmmmmmmm, This crow tastes great!!!




Good new is: My dumb ass did have the hammer spring turned the wrong way.


Bad news is: Holy crap the trigger pull on this thing is rediculous now. Time for a new trigger I guess.

The hammer pin still rotates with the hammer, so i will probably still go with the anti rotate pins. I think that is probably just a tolerance issue, unless you guys have another idea.

Thanks all for the help!!

[jscwerve]

They should rotate a bit, that's normal.

Anti-Rotation pins save wear and tear on lowers in high stress applications (full-auto, 9mm, etc) but are harder on the hammer/trigger/disconnector. Its a trade off in the big scheme of things. I use them because lowers receivers are harder/more expensive to get than internals. Even then, they're generally not needed.

That's why I'm still gonna go with the anti rotate pins. They are cheap, the lower reciever isn't. no, it's not going to see full auto use, but it will see many many thousands of rounds. Thanks again!

[BPTactical]

No need for a new trigger.
PM Sent