The AR-MPR Upper Assembly shown here during test fitting of components – Click here for larger view – Images Copyright 2010 Ultimate Reloader

Before we actually start with the build process for the AR-MPR rifle, I want to post some information about the parts and tools that are required for such a build. In this post, I’ll give a summary of the parts that will make up the AR-MPR upper assembly. I looked to Larry Weeks at Brownells for guidance on what to choose for components to meet the requirements for this project (benchrest shooting, varminting, and .5 – .75 MOA accuracy goal). Larry was kind enough to help me plan this build, and talk through the issues and decisions related to planning a build.

If you are planning a build like this (A3/A4 style upper, longer barrel, etc) you can use this list as a template for your parts acquisition endeavor. I’ve already done a test fitting of some of these parts, and found that I had the wrong gas tube! It always pays to take your time, and measure three times and cut once as they say in the woodworking industry (OK, we’re not really cutting here, but you don’t want to be stuck for a week or two on backordered parts while your buddies are out shooting at the range do you?).

So here’s what we’ll use for the upper components for the AR-MPR rifle (links to Brownells product pages provided here):

Stripped Flattop Upper Receiver (D. S. Arms)
This is an A3/A4 style flat top upper receiver (no internal parts). Precision Forged From High-Strength 7075 Alloy For High Quality Custom Builds. You could think of this as the frame or foundation for our upper. Everything will get held together by this chunk of aluminum.

Mid-Weight Barrel w/ultra-low-profile steel gas block (SABRE DEFENCE)
20″ fluted stainless steel match-grade barrel in 5.56 NATO chambering with compensator. This is one of the most important components when you consider the accuracy goal that we’re going for here. A match grade barrel is a must here, and I’m hoping the compensator will help with accuracy as well (blows some of the turbulent gas flow away from the base of the bullet as it leaves the barrel).

AR-15/M16 BOLT/CARRIER ASSEMBLY (Double Star)
Mil-Spec Dimensions For Drop-In Fit; MPI Inspected For Soundness. This bolt carrier group is pre-assembled, but we’ll take a look at stripping and re-assembling it as you would when cleaning the gun.

AR-15/M16 CHARGING HANDLE WITH TACTICAL LATCH (Sog Armory)
Extra Leverage For One-Hand Operation. This is a nice component. I’m picturing myself on a coyote hunting trip in the winter operating the rifle with gloves on. The large latch lever will be easy to actuate even in these demanding conditions.

High Standard Upper Receiver Parts Kit, FF Rifle (Brownells)
High Standard Upper Parts Kit includes ejection port cover, ejection cover hinge pin, ejection cover hinge clip, ejection cover spring, forward assist plunger, forward assist retaining pin, forward assist spring, 20″ gas tube, gas tube roll pin, flash hider washer and peel washer.

**Note that I ordered a mid-length gas tube as the 20″ gas tube in this kit was not compatible with the barrel I’m using.

T12 Free-Float Handguard (Midwest Industries)
Quad rail 12″ free float handguard. Definitely an impressive component. Full of versatility that we’ll use to mount a bipod, and other accessories. Free floated to maximize accuracy. This handguard comes with its own barrel nut that allows the handguard to thread on one side, and has a jam nut so that you can fine-tune the position of the handguard.

There you have it- the basic building blocks for an upper receiver. There are some additional accessories that I’ll leave for later. I’m really happy with how the parts look and feel (threading on the handguard, etc) – and I’m really looking forward to the final assembly of this upper. Part of that process will be sharing the HD videos of the process with you all.

Thanks,
Gavin