AR Hammer/Trigger Pins Fall Out

[patio]

I have been shooting 5.56 from this lower for over a year without any issues, today I threw on a new .22 upper and after a few mags the hammer pin and trigger pin fell completely out. The pins are from an RRA LPK and the trigger is a Timney drop in. When I replaced them they would literally slide right through.

Any suggestions? Short of buying a few brands of pins and seeing what happens I am stumped.

EDIT: Or suggestion on anti-walk pins would be appreciated.

 

[Scrivener]

1. C-clip pins. My drop-in kit came with bullet-proof pins; oversized, grooved and equipped with C-clips to keep them from migrating. However, they are somewhat ugly, installing/removing them can scratch your receiver and they are inclined to snag on things.

I ignored the ones that came w/the trigger unit and used the original factory pins, which have not moved since I put them back in. That obviously has not worked for you.

2. You might consider a VERY judicious drop of GREEN Loc-Tite on the last 1/16 inch protruding before you insert the pin back fully. You do NOT want Loc-Tite in the trigger group and you don't want anything stronger, in case you have to remove the pins again.

Don't forget to clean the pin and the receiver with brake cleaner or a similar solvent to make sure the Loc-Tite is not dealing with a contaminated surface.

 

[vellnueve]

You could also consider the KNS anti-walk pin set

 

[m4bushy]

JP makes some nice pins. They have a small button head screw that threads into each end of the pins. Plus they are slightly oversized so they are a press fit into the reciever.

 

[Dan S]

You don't need anti walk pins with a Timney AR trigger. Standard pins are fine. Tighten the setscrews in the trigger housing, and put the lock screws on top.

 

[Twigg]

...never mind, found 'em.

 

[vellnueve]

JP is their full name. They make AR15s in racegun form.

 

[patio]

Thank you all for the responses, I think that covers it. Dan's post reminded of those setscrews which did the trick but I already placed an order for the KNS no-walk pins so I will still install those as well.

 

[Steve_P]

1. C-clip pins. My drop-in kit came with bullet-proof pins; oversized, grooved and equipped with C-clips to keep them from migrating. However, they are somewhat ugly, installing/removing them can scratch your receiver and they are inclined to snag on things.

I ignored the ones that came w/the trigger unit and used the original factory pins, which have not moved since I put them back in. That obviously has not worked for you.

2. You might consider a VERY judicious drop of GREEN Loc-Tite on the last 1/16 inch protruding before you insert the pin back fully. You do NOT want Loc-Tite in the trigger group and you don't want anything stronger, in case you have to remove the pins again.

Don't forget to clean the pin and the receiver with brake cleaner or a similar solvent to make sure the Loc-Tite is not dealing with a contaminated surface.

If you are talking about 680 retaining compound or similar, I would be very cautious when applying this to your pins. It doesn't take much of it, and it will lock up your pins tight. You will probably have to use a bit of heat if you ever need to remove them.
Scriv is also right about it not sticking if the surfaces are not VERY clean. Rubbing alcohol also works well to clean the contact surfaces.

I would think the KNS pins might be worth a shot, with the retaining compound as a last effort.

Steve

 

[Gammon]

You could also consider the KNS anti-walk pin set

I put a set of these pins in my AR and, after about 10,000 rounds, the trigger developed some creep. Disassembly revealed that the pins were badly worn and scored. I replaced them with a set of JP pins. Much better part for less than half the price.

 

[Gammon]

PS I put a Timney drop in kit in one of my ARs. It creeped so badly that I returned it to Brownells.

 

[Rob Boudrie]

Standard AR triggers have a sprint in the hamemr (the "J Spring") that engages a notch in the center of the trigger pin so it won't walk out. Some other trigger configurations (particularly match triggers) don't have this spring and requires anti-walk pins. The current JP pins use a round head hex screw, and are best used with a bit of blue loctite on the threads. The older JP anti-walk pins uses a C clip, which was fine too as long as you used a plastic tool (such as a PDA stylus) rather than metal screwedriver to pop the C clip off.

JP is their full name. They make AR15s in racegun form.

www.jprifles.com

 

[patio]

Thanks again all. Weighed all the suggestions and feedback, including Gammon's (but this is a drop in trigger so is a non issue), and decided to go with the KNS setup.