The Sum of Its Parts, part XXXVII

Minus the OPS Inc 12th model suppressor and Pelican case, this MK12 Mod 0 is done, baby. I was waiting on the ARMS bipod adapter to finish her off. I haven't had a chance to try out the 123 grain Hornady A-Max rounds yet, as mother nature is showing her ass right now, but I intend to as soon as possible.




As promised, here is the build sheet for all the parts I had to order:
Upper Receiver - Les Baer
Lower Receiver - DPMS
Bolt - Les Baer
Bolt Carrier - Les Baer
Firing Pin, cam pin, retainer - DPMS
Gas Tube - Brownell's
Muzzle Brake - OPS Inc 12th model .30 caliber
Selector, Ambi - DPMS
Buttstock, A1 - Fulton Armory
Trigger - Geissele SSA
Lower Parts Kit - DPMS
Scope Rings, ARMS #22 Medium - ARMS
Scope Ring Cap - ARMS
Scope Tactical Ring Rail - ARMS
Scope, 3-9x42 Mil/Mil - SWFA Super Sniper
Charging Handle, PRI Gas Buster - PRI
Pistol Grip - ERGO
Gas Block, flip up front sight - PRI
BUIS, ARMS #40L - ARMS
Handguard, free float - PRI Gen III
Upper Rail, ARMS Peq-2-3 - ARMS
Barrel, .264 LBC-AR - Les Baer
SPR 18" Barrel contour with sight flats cut, 5/8x24" threading - ADCO
Sling mount, H&K loop - GG&G
Sling mount, buttstock H&K loop - GG&G
Harris 6-9" Bipod - Harris
ARMS #32 Bipod Mount - ARMS

Once I got the upper from Les Baer, a quick fit check showed that it didn't fit right on the DPMS receiver, so I called them. I told the nice woman on the line what was going on, and she just told me to hold on one minute, at which point Les Baer actual got on the phone and told me I had to do some fitting to make it work. He mentioned that I could buy some other brand of receiver that would fit without any work, but that it wouldn't shoot as well because it wouldn't be as tight a fit.

Taking his advice, I used a piece of 300 grit sandpaper on a flat of wood to very carefully fit the receivers, and it worked excellent. Here's a couple of phone pics:



Working the bottom of the upper receiver, I would very often fit check on the lower, until I had about 1/8th of an inch before it closed:



I did have to do some fitting on the rear takedown pin hole as well, which Les keyed me in on. No problem whatsoever. Now the receivers are tight as a drum, and I don't have to use an accuwedge.

Counting the lower receiver, this project took me over 3 years. I didn't really get serious about it until the beginning of this year. Since the .264 LBC cartridge is a mild cartridge, I hope the barrel lasts for 10k rounds or more. I'll post a range report again once I get a chance to shoot it at range.