bob35614 Posted September 7, 2016 Report Share Posted September 7, 2016 Hello to all, New member has a ? for all you builders. Have a Aero M5 DPMS 308 upper and a keymod 15" 308 handguard with barrel nut. Putting on the barrel nut until its as far as it will go on there is a gap between the parts as picture shows. The rail only slides on this far and the holes for mounting screws match up at this position. The place where I bought the rail said it would work with the Aero upper. I have built a few AR 15's before but the 308 is all new to me with all the different type parts. What is the reason for this gap? I would appreciate any help you folks can offer to me. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
shepp Posted September 7, 2016 Report Share Posted September 7, 2016 Welcome to the forum feel free to post in the intro section Quote Link to comment Share on other sites More sharing options...
EasyEJL Posted September 7, 2016 Report Share Posted September 7, 2016 Did the barrel nut come with the rail, with the barrel, or with the upper? Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted September 7, 2016 Report Share Posted September 7, 2016 What brand is the rail? Quote Link to comment Share on other sites More sharing options...
bob35614 Posted September 7, 2016 Author Report Share Posted September 7, 2016 2 hours ago, EasyEJL said: Did the barrel nut come with the rail, with the barrel, or with the upper? The barrel nut came with the rail. Thanks for the reply. Quote Link to comment Share on other sites More sharing options...
bob35614 Posted September 7, 2016 Author Report Share Posted September 7, 2016 1 hour ago, edgecrusher said: What brand is the rail? It's from a machine shop in CA that makes them for Palmetto Arm. and a couple rifle mfg.. It's a real nice quality made rail but that does me no good if I can't use it. Thanks for reply. Quote Link to comment Share on other sites More sharing options...
shepp Posted September 7, 2016 Report Share Posted September 7, 2016 3 minutes ago, bob35614 said: 1 hour ago, edgecrusher said: What brand is the rail? It's from a machine shop in CA that makes them for Palmetto Arm. and a couple rifle mfg.. It's a real nice quality made rail but that does me no good if I can't use it. Thanks for reply. Did you contact them?? Quote Link to comment Share on other sites More sharing options...
EasyEJL Posted September 7, 2016 Report Share Posted September 7, 2016 With all the grease in the pic, it's hard to tell what the gap is between the bottom of the barrel nut and the receiver. Quote Link to comment Share on other sites More sharing options...
DNP Posted September 7, 2016 Report Share Posted September 7, 2016 Might be worth taking it apart and getting some dimensions. Detail out the barel nut. The Aero upper should be fine, but check all of the thread dimensions and maybe someone here can compare. I'd go with Shepp and say a phone call to the machine shop that made the rail could be a good start. It's possible they've seen the issue before and might point you in the right direction fast. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted September 7, 2016 Report Share Posted September 7, 2016 Give the barrel a tug. Does the barrel wobble? If it moves, the nut isn't screwing on far enough. If it doesn't, the nut is out of spec. If it's the upper, I would guess that the threads on the upper we're not completed or finished. It could be as simple as too much material/finish on the threads. Have you tried a different barrel nut yet? If a different nut fits, then the original nut needs to be addressed. If the second nut doesn't work out, the upper is out of spec. A barrel nut should be worked on and off 3 or 4 times to ensure its seating all the way back. You can clean up those threads with a wire brush really fast. A brass wheel on a dremmel is even faster. Needless to say. The gap is definitely too large. Quote Link to comment Share on other sites More sharing options...
blue109 Posted September 7, 2016 Report Share Posted September 7, 2016 (edited) Did you thread the nut on the bare upper by itself just to check the threads are right? No rail or barrel? It should spin on without any trouble. If not, they may have sent you an AR10 nut. Edited September 7, 2016 by blue109 Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted September 7, 2016 Report Share Posted September 7, 2016 2 hours ago, blue109 said: Did you thread the nut on the bare upper by itself just to check the threads are right? No rail or barrel? It should spin on without any trouble. If not, they may have sent you an AR10 nut. Yikes! That could be devastating to the aluminum... depending on how hard one torqued on it. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted September 7, 2016 Report Share Posted September 7, 2016 I guess the barrel extention could be too thick too. While it's not likely, we've definitely experienced stranger things here. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted September 7, 2016 Report Share Posted September 7, 2016 Too much grease , can't see fitment . Define as far as it will go , is this with the barrel in the Upper Receiver ? Did this Hand Guard come with instructions ? How does the Barrel Nut fit in the Hand Guard with out it mounted on the Receiver . If you threaded an AR 10 Barrel Nut on there , the Upper Is probably toast ! Quote Link to comment Share on other sites More sharing options...
DNP Posted September 8, 2016 Report Share Posted September 8, 2016 Eh, it wouldn't be toast. JB weld can fix anything. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted September 8, 2016 Report Share Posted September 8, 2016 7 hours ago, DNP said: Eh, it wouldn't be toast. JB weld can fix anything. OOOOOOO K ! Quote Link to comment Share on other sites More sharing options...
DNP Posted September 8, 2016 Report Share Posted September 8, 2016 Just ask Rob and MaDuce! seriously though. Don't JB weld it. That's horrible advice. Was the index pin fully into it's slot when the barel nut went on? That's about the distance of your gap. And for the record this is not my photo...borrowed from online and cannot credit its owner. Quote Link to comment Share on other sites More sharing options...
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