AR-15 lower assembly issue(s?)

jquirit · Aug 16, 2009

Hello gentlemen. Time to pick your brains.

I am in the process of assembling an AR-15 lower using a RRA LPK in a Denny's Guns billet lower. The issue I have ran into is what seems to be a tolerance/clearance issue between hammer, trigger, and safety assemblies.

The deal is this. I can assemble and install both the hammer and trigger into the lower and they both work (lock the hammer back, pull the trigger and the hammer releases (did this holding the hammer as to not snap forward and damage the receiver)). However when I attempt to install the safety switch, the rear of the trigger group sits up about an 1/16" into the channel which the safety switch is to be installed in, thus preventing the safety switch from being installed.

If I remove the hammer, the trigger returns to it's normal position (fully down) and I can install the safety. Installing the hammer makes the trigger non-op (won't cycle due to inadequate range of motion between the trigger group and the safety switch). Inspecting the trigger and hammer group, I can see some scuff marks on the trigger from where the hammer appears to be rubbing on the trigger (near the front).

Searching on the internet I haven't heard of any issues with the Denny's billet lower and being out-of-spec. Could I have gotten an out-of-spec RRA LPK?

the4thshake · Aug 17, 2009

If I understand what you are saying...It sounds like you need to fit the safety. You have to remove just enough metal so the trigger will function. I did it once but can't remember if I took the metal off the safety or the trigger.

Grizzly_A · Aug 17, 2009

Start with the simple....

The safety selector rests against the tabs on the left side of the lower right?

So if you lock the hammer back in place (ready to fire) the trigger should return to it's lowest position in the lower. You're saying that in that position the trigger still sits high and blocks the insertion of the safety selector?

krawl · Aug 17, 2009

Is the grip already on? If not, you may be the rare that needs parts fitted a little more. You'll want to very very slowly fit the safety, then test function. It's easy, you just don't want to go too far.

jquirit · Aug 17, 2009

Grizzly_A said:
Start with the simple....

The safety selector rests against the tabs on the left side of the lower right?

So if you lock the hammer back in place (ready to fire) the trigger should return to it's lowest position in the lower. You're saying that in that position the trigger still sits high and blocks the insertion of the safety selector?

I don't know what (exactly) happened last night but following how you said to assemble it, it now all fits. I must of not been locking the hammer back after assembling the hammer and thus not allowing the safety to engage. It was the little detail that tripped me up. Thanks for pointing that out. Now it seems to be going together correctly.

Thank you for the assistance! :s0155: