A buddy of mine got a good deal (whatever that means this day and age) on a DPMS AR10 upper that has no bolt. So he bought a bolt off of the internet and I asked what kind but he couldn't remember the brand of it. He went to stick it on his Armalite lower and the upper will not close on it. When I look at it the bolt appears to be sticking slightly out the back of the upper and when I compare the bolt to another AR10 bolt (both are 308s) it is slightly longer. The upper and lower will fit together with the other bolt in it. I'm not an expert by any means and have never seen this before but has anyone else had a problem like this? Is it really a matter of just shortening the bolt? Is there some other factor I'm not seeing? All input would be appreciated, thanks AR10001_zps7cc91df1.jpg Photo by XJ2001 | Photobucket AR10003_zps76bf5a50.jpg Photo by XJ2001 | Photobucket AR10007_zpsd534ee21.jpg Photo by XJ2001 | Photobucket AR10008_zpsfc7dc5e4.jpg Photo by XJ2001 | Photobucket
Gunsmithing AR10 help
- Thread starter K-tech
- Start date
Well I have some bad news for your friend. That DPMS upper is not compatible with an Armalite lower. The AR10 is not based on the same "mil-spec" as the AR15 and parts are not interchangeable as such. Sorry to be the bearer of bad news but he'll have to swap one. Maybe not such a good deal depending on what he can do in trade. Oh, and even to make it more confusing you can make an Armalite upper work with a DPMS lower although it's not a "tight fit" so to speak.
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Yep...that's it in a nutshell.
Armalite Pattern = AR-10, Noveske N6, Eagle Arms, etc.
DPMS Pattern = LR-308, Mega MATEN, etc., etc., etc. (there are a LOT of DPMS compatible mfgs)
You cannot swap uppers/lowers between those very different platforms although some small parts (pins, triggers, etc.) are compatible across the platforms to some extent.
A sneaking suspicion of this came to me while I was at work. Hey, no skin off of my back. Ill spread the bad news to him and tell him to find and different lower. Thanks for your help
Unless he just has to have that particular upper receiver group for some crazy reason (or he really DID get THAT GOOD of a deal on it), I'd tell him to ditch the DPMS upper altogether and buy one made for his current Armalite pattern lower!
I may be wrong but both the upper and lower are not DMPS. DPMS recievers are rounded at the back where the upper and lower come together. The Armalite, like the Mega Maten are angled like the one in the pics. A DPMS upper and Armalite lower will never mate and visa versa. If the receivers in the pictures will make together in any way they are the same and the problem is not receiver compatability. It may be a case of a DPMS bolt in an Armalite carrier. The Armalite bolt has a spring keeping the pin from slamming forward and causing slam fires. The DPMS does not. The Armalite is a bit longer. My guess is he has compatability issues with the bolt and carrier. Is the bolt fully closing on the chamber? Did you try to headspace it?
Ya I would have just got an entire Armalite rifle but that's just me I guess. I have not tried to headspace anything, but it seems to me to be fully closing. I tried putting the shorter 308 bolt into the rifle and it will close but you cant charge it and that bolt has the spring around the firing pin. The longer bolt is the one I have in the pics and that bolt does not have the extra spring around the firing pin. Not that I'm trying to be argumentative or anything but this what Im seeing. I knew this thing was a bad idea when I seen it walk through the door.
