AR15 Recce Build - P2 - Lower


April 6, 2008, 06:35 PM
Carrying on from Part 1 - Upper

Lewis Machine & Tool Company, Inc. (LMT)
Defender lower with SOPMOD stock (model L7LB2)

Chip McCormick Corp (CMC)
Super Match Trigger Group (model 91501)

TangoDown BattleGrip

Magpul Enhanced trigger guard


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April 6, 2008, 06:36 PM
The CMC trigger group dropped right in, no probs..
the safety/selector needed to be removed first..

Installed the provided pins (tight fit!) from the right with a plastic faced hammer..

To protect the receiver from scratches, I placed a piece of paper with small holes cut for the pins to protrude through and pushed the provided c-clips on using the edge of the plastic hammer head..

Using a small piece of 3/4" x 3/4" wood to support the fragile "ears", I drove the original roll pin that secured the trigger guard out using a Brownells roll-pin starter punch..Installation of the magpul trigger guard went smoothly, though the fit was tight..
Note the provided hex screw (on the right), screwed in until flush..
To touch up around the roll pin hole, I used a Birchwood Casey Super Black touch up pen..

Insert Brownells hammer drop block, pull trigger,
and :D


April 6, 2008, 08:05 PM
SOPMOD stock..

Storage tubes removed..

~LOP (length of pull) measured from center of trigger to include rubber stock pad (1/2" thick):

Position 1 : (fully collapsed) : 11-1/4"
Position 2 : 11-7/8"
Position 3 : 12-1/2"
Position 4 : 13-1/8"
Position 5 : 13-3/4"
Position 6 : (fully extended) 14-3/8"


April 14, 2008, 05:41 AM
Test and prep before first live-fire:
Brownells hammer block shown during CMC trigger test.

Safety test:
Hammer uncocked, safety should not rotate to SAFE position.
Hammer cocked, safety should be able to rotate from FIRE to SAFE and vice versa.
Safety on, give a good squeeze to the trigger .. hammer should not fall.

With safety off, squeeze trigger and keep it held back (if no hammer block, hold the hammer to keep it from striking the receiver or bolt catch) .. re-cock the hammer .. it should be caught by the disconnector .. slowly release the trigger .. the hammer should be handed off to the trigger.
Repeat a couple times and a couple more while pulling upward on the hammer.

Rotate to SAFE, the hammer must not fall.
Inspecting the trigger group for proper lubrication.
Removing the buffer assembly.
The safety should have been on during removal .. all good though.
Receiver extension (buffer tube) is filthy inside and no lube found.
Maybe it's dry lubed? I don't know, so out comes the cleaning stuff ..
Dewey chamber rod with 8-32 female threads.


April 14, 2008, 05:49 AM
8-32 to 5/16-27 adapter (brownells 234-000-056) and AR-15 receiver mop.
Into the extension it goes along with some aluminum safe cleaner.
A couple follow ups with dry towels.
Some ATF on paper towel goes in to nullify any remaining cleaner (esp. around the ext. threads) and to provide lube.
Hopefully this will improve the life of the extension/tube, not to mention the spring and buffer.
Keeping the receiver tilted to try and keep any excess ATF out of the lower reccesses and trigger group.
Removing excess lube from underneath the takedown pin.


April 14, 2008, 06:15 AM
Buffer assembly reinstalled and ready to go.

Once the upper is prepped, it'll be time to hit the range..


August 28, 2008, 02:09 AM
After trying the SOPMOD stock, I wasn't comfortable with it, so I'm gonna try something different .. anyhoo, here's how I dealt with..

Buffer Tube Removal:

The LMT lower assembly came with the buffer-plate staked in two places:

Craftsman 3/8 x 4.5" center-punch to drive back the stakings:

HammerTime: HammerDance not shown for your own well-being :p

DPMS multi-tool: Note the projection near my pinky .. it indexes to the notch(s) on the buffer-tube nut:


August 28, 2008, 02:10 AM
Once the stakings are dealt with, loosening the nut is fairly easy:

Restraining the buffer-plate while loosening the nut so as not to launch the takedown-pin spring:

Moved the buffer-plate out of the way to get the spring out:

Takedown-pin slides right out:


August 28, 2008, 02:12 AM
Keeping the buffer-retainer from launching while unscrewing the buffer-tube:

Note the projection on the buffer-tube .. it retains the buffer-retainer:

Receiver off the block and dumping the takedown-pin detent:

All the bits:


Installation - go in reverse, just make sure the buffer-tube is the correct type (mil or commercial), the right length and properly retains the buffer-retainer when test fitted :)
I'll try and get a good shot of it when I install the new buttstock assembly


August 28, 2008, 03:06 AM
Safety Remove/Replace coming soon ..


August 28, 2008, 03:07 AM
Looking nice :)

August 28, 2008, 03:09 AM
Thanks :D


Bartholomew Roberts
August 28, 2008, 07:57 AM
Thanks for a great post, Sylvan-Forge!

Dave Markowitz
August 28, 2008, 08:16 AM
Outstanding post!

August 29, 2008, 01:25 AM
Thank you gentlemen!


As promised, here's Safety Removal:

First, empty any grip contents:

Grip bolt shown:

Was pretty tight, so I put my allen-key into some locking pliers:

Removed bolt and carefully walked the grip off, taking care not to kink the safety spring:


August 29, 2008, 01:26 AM
Once the grip is off and safety spring is out, everything wants to fall apart .. don't lose your safety detent. Note the pointed end .. the point rides the safety's axle:

Push out the safety (if it hasn't fallen out already):

All the bits:

Installation reverse of removal: Safety, Detent (dab of grease then pointy end 1st), spring into grip, walk grip on (no kink spring) and tighten it down, test safety (see post #4 above).

Note: I guess I should have done this with the hammer lowered :)


Deus Machina
August 29, 2008, 08:23 AM
First, empty any grip contents:


August 29, 2008, 08:26 AM
love that stock.. I whish I could get one !

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