Friend's AR difficult to safe with bolt back?

[HeavyDuty]

A friend recently built his first AR on an Aero lower. He has a dehorned M16 hammer at the moment because he wanted an unnotched hammer.

He's having an issue that I can't immediately resolve. The selector works with no issues so long as the BCG is in battery, but moving it to safe with the bolt locked back takes major effort.

Any suggestions where to start? I'm thinking the hammer "tail" is pressing down on the trigger or disconnector when the BCG is back.

[Quib]

It could be that the FCG pin holes are not drilled in the correct location on the lower.

ETA: I just tried to duplicate your friends problem on one of my ARs, by separating the upper from the lower, then while holding pressure down on the hammer, I placed the selector on safe. I could not duplicate the problem. You might start by trying the same.

[HeavyDuty]

We did try that and had the same resistance.

I'm wondering if maybe he didn't cut enough of the tail off the hammer and combined with an AR bolt carrier this is the issue?

[Quib]

We did try that and had the same resistance.

I'm wondering if maybe he didn't cut enough of the tail off the hammer and combined with an AR bolt carrier this is the issue?

That could very well be.

Does he have access to a semi-auto hammer he could use for comparison? Match up both hammers, then see where any more trimming may need to take place.

[HeavyDuty]

I'll suggest that to him - thanks!

[Stickman]

Who makes the weapon?

[HeavyDuty]

It's an Aero lower with an unknown LPK, possibly M1S. I think he found the hammer separately.

I suggested he swap out the entire FCG including selector with a friend and see what happens.

[Stickman]

That sounds like a good idea.

[Ryo]

Definitely good idea.. it will determine if the problem is with the lower or the parts.

[Lastrites]

Long shot, pistol grip screw is protruding through making contact with tail of the trigger pushing it up providing the resistance.

[Quib]

Long shot, pistol grip screw is protruding through making contact with tail of the trigger pushing it up providing the resistance.

Good point. Might be worth looking into.

http://farm3.static.flickr.com/2622/4242485920_e6e940355a_o.png

[HeavyDuty]

Grip screw was the first thing we tried...

[Quib]

Grip screw was the first thing we tried...

To help those who are trying to help you....how about a list of things you’ve done up to this point. [:)]

[HeavyDuty]

To date, we tried swapping out the hammer and trigger with a spare and also backing off the PG bolt. We didn't have a spare selector at that time. We then tried stoning the tail of the hammer which seemed to have some effect but didn't totally resolve the issue - it can now be safed with the BCG back but it requires more effort than normal, and much more than safing with the BCG in battery.

He's two states away, and I suggested he temporarily swap the entire FCG out with a local friend to see if it helps; if it doesn't, I suggested he contact Aero regarding a replacement lower.

Thanks, all!

[DDriller]

Some of the safety selectors that have come out recently have some fairly large ridges on them that need to be filed off. The last DPKS kit I got was like that. I don't use the FCG from the kit as I use Geiselle triggers in most of my rifles.

[cagilber]

Could there be a problem w/ the safety selector detent spring inside the grip?

[HeavyDuty]

Could there be a problem w/ the safety selector detent spring inside the grip?

Unlikely - we loosened the PG to check that the retaining bolt wasn't too long and still had the issue.

[moneey]

I also would like to know because I also have the same issue. lmt piston upper on pof gen 3 lower with dpms lpk and moe grip&screw. I noticed the selector groove for detent was not a "smooth" groove. does your friend's selector look like that? if so, could that be the issue and what could be the fix if any?

[HeavyDuty]

Sadly the AR in question is two states away, go I have no idea...

[Lastrites]

So did this ever get resolved? Came across a possibility. Did he change out and put on a new pistol grip? If so could the detent spring hole in the new grip be too shallow, creating a lot more force on the SL. This actually happened to me recently and caused a momentary [bash].

[HeavyDuty]

We did try that with no effect. He says it appears to be wearing in, that it's become much less difficult to safe it with the bolt back. I wish he'd swap selectors with someone though.