DPMS UPPER WARNING / REVIEW

[yesjesusknows]

I agree that had the OP known there was no mil-spec for AR-10 lowers then there wouldn't be any expectation of fitment but it appears OP did not know this. It isn't the mass manufacturing variance of this particular manufacturer that's the problem. It's a lack of mil-spec for 308 AR-10 lowers that is the problem. AR-15 lowers are mass manufactured but they don't suffer from this same problem nearly as bad as AR-10 ones do because of the fact they are mil-spec. I think the AR-10 lower manufacturers should get together and agree on a universal spec so that people don't run into this problem. Also, does it have any effect on locking in the rear takedown pin or how the upper functions or is it purely aesthetics?

The rear take down pin is properly working. As of now it is only
aesthetics as I have not fired the weapon.

[valley82]

Yeah that would bum me right out...
My two sons and I have three DPMS upper receivers and Diyarmory 80 lowers that fit up very well and all three fit the same when interchanged. I would be curious to see how your upper and lower differs from our three.

[kcstott]

I still don't know why this hasn't been solved with acraglass and recoating. It's good enough for the recoil lug of a safari rifle, it's good enough to solve fitment of an aluminum reciever.

Because it should have been machined right to begin with and the last time I checked Acraglass don't anodize.

I'd trash the upper and buy a TM and be done.

[Gigantor]

So other than CMMG uppers, which ones fit the 80% arms lowers without the gap?

[jaymz]

My DPMS upper fits my HH Tactical lower perfectly.

[kcstott]

I agree that had the OP known there was no mil-spec for AR-10 lowers then there wouldn't be any expectation of fitment but it appears OP did not know this. It isn't the mass manufacturing variance of this particular manufacturer that's the problem. It's a lack of mil-spec for 308 AR-10 lowers that is the problem. AR-15 lowers are mass manufactured but they don't suffer from this same problem nearly as bad as AR-10 ones do because of the fact they are mil-spec. I think the AR-10 lower manufacturers should get together and agree on a universal spec so that people don't run into this problem. Also, does it have any effect on locking in the rear takedown pin or how the upper functions or is it purely aesthetics?

Mil spec is not the answer. 90% of the AR stuff on the market is not Milspec.

They may claim mil spec but unless they actually manufacture for the military and have a approved QC system ISO 9000/12000/14000 what ever It ain't milspec


In the U.S. during the 1980s and early 1990s, it was argued that the large number of standards, nearly 30,000 by 1990, imposed unnecessary restrictions, increased cost to contractors (and hence the DOD, since the costs in the end pass along to the customer), and impeded the incorporation of the latest technology. Responding to increasing criticism, Secretary of Defense William Perry issued a memorandum in 1994 that prohibited the use of most defense standards without a waiver.[3] This has become known as the "Perry memo". Many defense standards were canceled. In their place, the DOD encouraged the use of industry standards, such as ISO 9000 series for quality assurance (see COTS), SAE standards such as the AS and AMS series (e.g., AS9100, AMS 2404), and others. Weapon systems were required to use "performance specifications" that described the desired features and performance of the weapon, as opposed to how those goals would be reached (that is, exactly which technology and which materials would be used). In 2005 the DOD issued a new memorandum[4] which eliminated the requirement to obtain a waiver in order to use defense standards. The 2005 memo did not reinstate any canceled defense standards.