AR Roll Pin Size Question

[tRidiot]

The hammer spring must be placed in such a way that it exerts the most possible force on the trigger pin. For this reason, a lot of people think when installing it that it can't go that way, you really have to push down hard on those spring "legs" on top of the trigger pin to get it oriented in the right place to insert the hammer pin.

The symptoms you're describing are exactly what happens in this scenario. The hammer spring exerts enough force for the trigger to work fine - for a while. Without that extra pressure, however, over time (usually just a couple hundred rounds or less), the trigger pin will "walk" out of position. You can replace it in the right position and it will happen again in a few more rounds.

Here's a good picture of the proper orientation:

[Broken External Image][Broken External Image]

 

[SPDguns]

Ok, been away watching the game, so will try to catch up and address all the great suggestions.

I would suspect it has had way less than 100 rounds through it, so I would think wear on the pin or holes should not be a problem unless an old pin was installed for some reason. The pin was not shiny on the ends as an older one might be if it was worn and previously flopping around in a hole.

I have only pushed the pin back in to finish up firing at the range, then poked it through both directions about a 1/4 inch to measure it for the .154 inch size I posted. It has some resistance, but about half less than other pins similar I have pushed out.

I will have to do some research on the spring orientation and take a look. I am not as familiar with AR's as I would like to be, so this will be good for me to understand how it should be installed. The trigger felt as I expected for a stock fairly new unit even though the whole assembly was almost dripping with oil.

I'll take a look at the spring, if not the problem, will pick up a new pin in case this one might be odd sized and out of spec for some reason, then go from there. As a last resort, most likely a dot of blue Lock-tite or Vibri-tite would take care of the problem, had that on my might need to do list, but wanted to look at other options first. It has some resistance in the hole, just slightly less than it should.

SPDguns - I so appreciate the offer but I am about 30 miles East of Tulsa, so not real close, let me catch up on looking at the spring and putting in replacement pin, and I will post what I find.

Thanks to everyone for suggestions.

I'll be in the Tulsa area next Sunday and Monday. I'll fix it for free. Maybe a cup of coffee if it's real bad..!

 

[p238shooter]

Thanks to everyone trying to help with my issue, and a special thanks to tRidiot for the picture above.

It is said that a picture is worth a thousand words, it's true most of the time. I popped it open, glanced at the picture again then took a 3 second glance into my lower.

Yep, there is the problem. Spring installed backwards just as several of you suggested looking for. EZ fix, well sorta, I may have bent my thumb getting it back in, Ha Ha.

Thanks again guys.