natedavis49686 Posted September 5, 2014 Report Share Posted September 5, 2014 Hello, This is my first post/introduction. I am an enthusiast/hunter/shooter/guide. Ever since my first AR build, I've been hooked! I'm finally starting my first large-frame build, and have a quick question... For a wedding gift, my groomsmen pitched in to get me a lr.308 "custom lower". I purchased a DPMS upper to get this rifle started, but there is a serious gap back by the extension. I know there is always a little gap, but I am concerned with this amount (attached) Is this a lower receiver issue? Or is the DPMS upper out of spec? Thanks a lot for any help or advice on how to proceed! -Nate Quote Link to comment Share on other sites More sharing options...
EasyEJL Posted September 5, 2014 Report Share Posted September 5, 2014 does it jiggle much? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted September 5, 2014 Report Share Posted September 5, 2014 There are a whole lot of possibilities here, I'd try to locate another upper and check it too. If it also has a large gap, the dimensions on your lower could be wrong, possibly something as simple as a mislocated forward retaining pin hole. If no gap with a different DPMS type upper, most likely the upper is out of spec. Quote Link to comment Share on other sites More sharing options...
AdamO Posted September 5, 2014 Report Share Posted September 5, 2014 That's the problem with the whole .308 AR world. There is no mil spec like there is with the AR15 so there are no guarantees that everything will be plug and pray. The best rule of thumb is to source your upper and lower from the same place but in your case it was a gift and it's a custom piece so what do you do? Maybe the place that made your lower has a matched upper that they sell with it? That gap might be a concern and it might not. have you run any ammo through it yet? Does it cycle properly? For reference, here is a pic of how my Aero Precision upper and lower fit together. Bought them together as a set. It's a pretty tight fit. Quote Link to comment Share on other sites More sharing options...
natedavis49686 Posted September 5, 2014 Author Report Share Posted September 5, 2014 Thank you for the responses! There is a very small amount of "wiggle" at the front retaining pin. None of my M4 clones have this "wiggle" or any slop (they are all matched upper/lowers though). I'll try to find another upper and see if that may be the issue. Thanks again guys, -Nate Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted September 5, 2014 Report Share Posted September 5, 2014 Welcome from AZ nate! Quote Link to comment Share on other sites More sharing options...
unforgiven Posted September 6, 2014 Report Share Posted September 6, 2014 Welcome from Indiana brother Nate. Quote Link to comment Share on other sites More sharing options...
Gibbs Posted September 7, 2014 Report Share Posted September 7, 2014 Welcome from Michigan! Quote Link to comment Share on other sites More sharing options...
blue109 Posted September 7, 2014 Report Share Posted September 7, 2014 are you sure it's a factory DPMS upper? I could be wrong, but judging by the thickness of the metal over the charging handle slot it looks like it's the "old" DPMS height receiver. DPMS hasn't made those in a few years, but several other companies still use that height standard. it would be odd to buy a new DPMS upper and get the old style. again...this is just a guess from looking at that pic. my eyeball might not be calibrated. Quote Link to comment Share on other sites More sharing options...
blue109 Posted September 7, 2014 Report Share Posted September 7, 2014 I pulled miss piggy out to compare, and on second glance your gun does look about right for a newer DPMS height. I just like any excuse to pull miss piggy out. Quote Link to comment Share on other sites More sharing options...
Rsquared Posted September 9, 2014 Report Share Posted September 9, 2014 Welcome from MD Nate. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.