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6/5/2017 2:49:49 AM EDT
Question for those in the know......RRA lower, Anderson Upper.........When the forward takedown pin is engaged and the upper is pivoted rearward to latch the rear takedown pin in place. The upper does not swing down quite far enough to engage the rear pin.......This IS NOT a case of tight lug from the upper needing a mallet smack to seat but rather an upper that swings freely to within about a quarter of an inch of latching and then doesn't want to go any further without pressure..... I can close it by pressing it down and latching the pin but I have not seen one that did not seat and latch fully without coaxing. It "wants" to spring back open. Problematic? Will this pressure eventually crack something on either upper or lower if left unattended??? Any AR I have handled up to now has seated easily and some even rattle a bit.

Thanks in Advance.....

Steve
6/5/2017 4:45:20 AM EDT
[#1]
Does it stay closed and cycle correctly?  If so, you're fine.  A tight takedown pin/lug setup isn't going to damage anything.  Heck, some lowers have set screws that push up on that rear lug from the grip screw area to take up all the slack.
6/5/2017 5:00:15 AM EDT
[#2]
I had a set that I had to use a punch to help push the pins out.
6/5/2017 9:57:33 AM EDT
[#3]
Rjeff......

Absolutely stays closed and functions fine. Just concerned that forcing the upper down to allow the rear pin to pass thru and lock the upper in place might be straining the pivot points on the front of the receiver. Bear in mind that this is not a case of an overly tight pin fit in the hole or a case of the lug from the upper binding in a tight lower as both those conditions would easily wear in after a few opening/closing cycles.....Perhaps I am being overly cautious because I have never ran into one that had to be "squeeze fit" to lock up.
6/5/2017 10:33:24 AM EDT
[#4]
RRA lowers are notorious for a really tight fit.

I have to "press" mine together even after close to 1k rounds.

My upper is a Spikes Tactical.

Is your pivot hole in the front lug drilled too high?
6/5/2017 10:33:45 AM EDT
[#5]
When my rifle was new I had the same problem. Should get better with time.
6/5/2017 10:50:02 AM EDT
[#6]
Quote History
Quoted:
RRA lowers are notorious for a really tight fit.

I have to "press" mine together even after close to 1k rounds.

My upper is a Spikes Tactical.

Is your pivot hole in the front lug drilled too high?
View Quote
I'd have to compare it to another of my Anderson uppers and I imagine it certainly could be drilled slightly high. If that is the case, wondering if the strain imparted to the lug or pivot bosses in the lower  could result in cracking of either.....A hole that is slightly off on the upper could easily be remedied with careful fine filing.....I guess in a "perfect world" we are looking for that perfect, no strain, pivot into place but in the real world of "acceptable tolerances" the "squeeze fit" might be acceptable, as long as it is not excessive?????
6/5/2017 11:23:47 AM EDT
[#7]
I would check it against another upper.  I do not know the dimensions offhand.

As far as acceptable tension,  that's a call only you can make.

RRA LOWER DISCUSSION
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