In this second installment of the Mk 12 "Mod 3" project I go over the proper installation of a Geissele MK18 SMR ARCA-Swiss/MLOK Handguard onto an upper receiver paired with a Centurion Arms MK 12 Mod 0/1 18" Centurion SPR Profile 5.56 NATO (MK 262 Mod 1/C optimized) barrel.

The order of operations are talking about headspacing and demonstrating how to headspace gauge a barrel. As I am only using Forester gauges there is not a "fail" or NO-GO shown per se as the gauges show the absolute maximums for headspace. Again, this is a MK262-spec chamber so the headspace will be a bit longer.

I go over how to install and properly lube and wet-torque a barrel nut with the Geissele barrel nut wrench and Reaction Rod. Then I go over how to install and "gauge" that you bolt carrier, gas tube, and gas key are all within specification. Finally, I go over how to install the actual handguard, how to time it, the bits you'll need for it and do the outro.

I have to get glass for this weapon still and pick out a can for it as well, this just covers installation and overview of the project in an extended fashion where I definitely do not mess anything up or misspeak at all! (Just kidding, of course).

Timestamps
Intro: 0:00
Centurion Arms Shoutout: 01:57
Order of Operations and Housekeeping: 05:02
On Headspace: 06:29
223 REM vs 556 NATO Headspace: 10:39
Headspace Gauge Demonstration: 11:56
Barrel Install Overview: 13:59
Barrel Nut Install Starts: 17:06
Torque Wrench Setup: 19:04
Gas Tube Install Overview: 19:55
Gas Tube Install: 22:11
Bits needed for Handguard: 23:12
Rail Install Overview: 24:30
Outro: 25:58