AR lower parts

[Robocop1051]

This was originally posted on AR15.com by "Carbine_Man" on 12/30/2009

DPMS LR-308 Lower Receiver Assembly

Do not trust the schematics in the DPMS dealer catalog! Mine (2009) had many errors that I only discovered by accident. Having just tonight completed assembling my LR-308 lower, I though you might find this useful.

Essential LR-308 Lower Receiver Parts

Many AR-15 lower parts are compatible with the LR-308, but the parts listed here are NOT AR-15 COMPATIBLE and must be included in your build. DPMS part numbers to the left:

•308-LR-18 - .308 Front Pivot Pin

•308-LR-30 - .308 Rear Takedown Pin

•308-LR-11 - .308 Bolt Catch

•308-LR-12 - .308 Bolt Catch screw

Other things to note:

•The pivot and takedown pins are 9/32".

•The magazine catch, spring and button are AR-15, but when assembled correctly the threaded rod part of the catch will be about 3/16" short of flush. I used a 10-32 set screw ground to fit and filled the hole. It looks much nicer.

•The 308 Bolt Catch Screw has a 1/16" socket head. Very easy to assemble, just screw it snug, I used a little blue Loctite on the threads.

•The pivot and takedown pin detents and detent springs are the same, but the takedown detent comes up from the grip rather than from the back. I found that cutting a small (>1/32") divot in the grip to hold the bottom end of the spring kept the spring from squirming to the side while tightening the grip.

•All fire control parts, including the safety selector, are identical to AR-15. I installed a RRA NM 2-stage trigger with no problems.

Hope this helps,

[Robocop1051]

I found this on accident. This is going to save me a bit of money, as I have a HUGE surplus of extra AR15 lower parts. What was going to cost me between $50-$100, is now only costing me about $20!