I have a pre-ban DPMS Cast lower.  I am finding that I can not fit any other uppers on it (excluding the one that came with it).  When I try to put a different upper on, I can see that the take down pin hole on the upper does not match up with the hole on the lower.  If I push down hard enough on the upper and use a brass hammer I can hammer the take down pin in about 90% of the way, but I don't think this is a good solution.  What, if anything, can I do to make this problem go away?  I have a nice A1 upper that I would like to put on it, but so far that is not an option.  

Thanks for any help!  

Brad

I had a similar problem with my ZM, My problem was that I had the buttstock tube screwed in "One turn" or twist too far.

 Do you have the collapsing stock or solid stock?

 Good Luck!

I have an A1 stock on it.  I will try loosening it a bit and see if that helps.

Thanks!  

Brad

I tried backing off the buffer tube, but that did not help.  I still can't put any other upper on.  Any other thoughts?  

Thanks guys!

Brad

I think the simple to say (but hard to hear)answer is that it's out of spec.

Yeah, the lower sounds out of spec. You will need to take a round file and remove some material from one or both pin holes. Since the lower is by far the more expensive of the two receivers, [b]DO NOT[/b] file on it. Just custom fit all uppers to the lower individually. You really have no other choice. [:(]

After coming home from one of the most frusterating, anger days of work I have ever had, I checked the boards to see if there was any help.  After reading M4's post, I dut out the small round file and went to work.  15 minutes later and the problem is fixed!  It fits as well as the other upper I have for it.  

Thanks a lot guys.  You actually made my day!  

Brad

Brad --

Sorry I missed this message.  You [i]should[/i] have filed the pins, not the receiver.  Always modify the 50 cent part, not the $500 part.....

-- Chuck

The lower was out of spec, now it's not.  The lower will now work with different uppers.  

I think he did the right thing.