DPMS upper on RRA lower - will it fit? DPMS says no.

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gunsrfun1

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Guy at DPMS insisted that DPMS .223 uppers/lowers are not compatible with RRA uppers/lowers due to the takedown pin configurations. And he said other companies like Bushmaster and Remington also won't fit RRA. I called BM and they said they were not aware of such an issue.
I've never heard of this issue either. Is he right? (I asked if he was talking about the trigger pins, which I am told RRA's are slightly larger, but he said, no, the two takedown pins are not compatible and a DPMS upper won't fit on a RRA lower.)
Thanks
 
Sounds like DPMS Tech support is getting as bad as their Rifles.

Unless one of them is badly out of spec then they will fit together just fine.
 
RRA has historically made their uppers and lowers with a super tight fit. Part of the reason was a long time ago the AR culture complained about play between the uppers and lowers. The RRA rifles I've had experience with required a hammer and a punch to remove the pins at first. Over time they would loosen up but the receivers would still fit nice and tight.

The guy at DPMS is clueless. Sometimes I wonder how these people even get hired. If I need to have two 1 hour interviews before getting a job, shouldn't they be having some serious technical discussions before hiring a guy to take tech questions from customers?
 
I'm pretty sure that DPMS 308 caliber uppers and lowers won't fit on RRA uppers/ lowers b/c there is no milspec for 308/ 7.62 and there are two competing sets of specs. Since most ar-15 in 5.56 are milspec they should be compatible. As a matter of fact I have a DPMS lower mated to a colt upper and it fits fine. I'm sure there are more knowledgeable people here who can tell you the exact 308 what will and what won't fit.
 
I have a DPMS lower that runs 3 different uppers. Sounds like BS, or confusion with their .308 platform.
 
Thanks all. You confirmed what I suspected. I am actually considering mating their DPMS Oracle upper to my RRA lower as a "fun" and "sort-of-tactical" combo (zombie sightings in my area are rare). Not crazy about the lightweight barrel, but the price is right ($400 @ Midway) and it's gotten good reviews. Just didn't want to be surprised that it wouldn't fit.
 
I had a RRA upper on a CMMG lower, no issues whatsoever. I did trade a guy for a RRA lower so the finish would match, and the fit went from slightly loose, to very snug with the RRA lower.
 
gunsrfun1 said:
Guy at DPMS insisted that DPMS .223 uppers/lowers are not compatible with RRA uppers/lowers due to the takedown pin configurations. And he said other companies like Bushmaster and Remington also won't fit RRA. I called BM and they said they were not aware of such an issue.
I've never heard of this issue either. Is he right? (I asked if he was talking about the trigger pins, which I am told RRA's are slightly larger, but he said, no, the two takedown pins are not compatible and a DPMS upper won't fit on a RRA lower.)
Thanks
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False. Just ask floorit76. He had a DPMS 6.8 on a RRA lower.
 
Yes sir I do. Pins slide out easily, don't even need anything but fingers. Haven't fired it though. :cuss:
 
I have a RRA lower with a DPMS upper. The fit is snug like it should be. Admittedly the RRA lower was made when they were in their original location. Are you sure he was not talking about the LR308?
 
The issue is RRA lowers are made on the tight side on the rear lug. Depending on tolerance stacking between the upper and lower, the upper may be any where from a very snug fit to you have to hammer it closed. This also causes the pin to be very tight sometimes. A lot of people will see this as a defect, not being able to close the receivers together.

Often, the parts will wear in and just remain snug. It's easier for the tech to tell you it won't work vs. newbies calling and complaining daily.

.308s on the other hand aren't close.
 
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