AR Trigger/ hammer retaining pin issues

**Andy37** · 03-02-2014, 08:36

I am having issues with the trigger and hammer retaining pins in my M4. I think I have solved the trigger pin problem by using the hammer spring to lock it in place, but cannot stop my hammer pin from migrating sideways until it pops loose. Any thoughts on what can be done, or what I'm missing here? Thanks in Advance.

**Lian** · 03-02-2014, 08:48

you could always get those anti-rotation pin sets. and it's an actual legitimate reason for getting them, other than it just looking really cool

http://www.brownells.com/rifle-parts...prod26944.aspx

DS · 03-02-2014, 10:22

The hammer has a straight wire retaining spring that that catches on the pin detent groove - look through the pin aperture of the hammer and see if you can see the spring protruding. It may have broken off and fallen out.

You will also see the top of the spring if you look at the hammer form the bottom and if you look at the small hole above the pin aperture.

Also check if your hammer pin has a detent groove in the middle where the spring will catch the pin.

If the detent spring is broken or absent you will need to replace the hammer imo.

We have a few ALG Defense triggers is stock and some CMC trigger modules if you consider replacing/upgrading the whole trigger group.

**Andy37** · 03-02-2014, 10:45

Thanks Deon, that's the info I was looking for. The hammer pin has two detent grooves, one is in the middle so that's GTG. I'm assuming the hammer detent spring has broken, do you have any replacement hammers in stock?

DS · 03-02-2014, 10:53

No we do not have only the hammer for sale , sorry.

I think you will be able to order it from Brownells as it will be under $100 value.

**Andy37** · 03-02-2014, 10:55

Thanks again Deon, I'll source one somewhere!

DS · 03-02-2014, 11:04

If you get the anti-rotating pins Lian suggested you can use your current hammer.

**Andy37** · 03-02-2014, 11:07

I need to mic the existing pins and see if I can get away with a (oversize).155" set, they are backordered on the standard .154" sets. Will check tonight

**FNBROWNING** · 03-02-2014, 11:37

Originally Posted by Andy37

Thanks Deon, that's the info I was looking for. The hammer pin has two detent grooves, one is in the middle so that's GTG. I'm assuming the hammer detent spring has broken, do you have any replacement hammers in stock?

With the hammer and pin out it is fairly easy to see if the J'spring is broken,even just pushing the pin through the hammer will show if the pin clicks into place or not. If the j'hook is broken oversize pins will make no difference. If however the J'hook is still ok then it may well be slightly oversize pin holes; likely to be the first though. I doubt you will get a hammer on its own and even if you do there is no guarantee it will mate well with your sear if from a different manufacturer. Having had a similar problem I installed a Wilson trigger but a tad pricey.