AR-MPR: Phase II – Rifle Accurizing Plans

I just read a great article written by Robert Whitley of fame that was posted on the blog:

What Makes an AR Accurate — Whitley Offers Answers

Talk about good timing! This post helped me plan the first wave of accurizing activities for the AR-MPR rifle. My goal is to remove any factors that will prevent consistent groups – part of that is related to precision handloading, another part is related to the rifle and related equipment, and finally- shooting techniques and skill. In this post, I’ll outline some plans I have for addressing the second group of concerns listed here.

Let’s walk through the first pass at these accurizing activities:

Improved Stock

The AR-MPR currently wears a standard 6-Position collapsible stock. I thought this would be nice for compactness when carrying in the field, and so that it would be easily stowable/storable. I was a bit concerned that this stock would be too wobbly- and it does indeed impose more movement than is acceptable. The answer is to upgrade to a Magpul PRS adjustable stock- this stock was designed for this type of use, so this should help tighten up the back half of the rifle, and afford optimal shooting ergonomics. The flat bottom will be ideal for riding straight back in the rear rest.

The Magpul PRS Precision Adjustable Stock - Click for product page

The Accu-Wedge

One of the simple upgrades that you can make for your accuracy-minded AR-15 is a drop in part called the “Accu-Wedge”. The purpose is simple- take the wobble between the upper and lower units away. No, this wedge does not make the upper “rock-solid” against the lower, but it does help to keep it steady – which translates to keeping your groups tighter!

The Accu-Wedge - Click for product listing at Brownells

Front Bench Rest Rider (Custom)

In order to complement the Magpul PRS – I’m planning to machine a custom front bench rest rider. This will clamp onto the bottom rail of the handguard, and will allow the rifle to move straight backwards under recoil rather than “jumping up”. More details to follow on this project!

This project was inspired by the EGW bag-rider (great if you have a round handguard):

EGW Bag-Rider System

These improvements, combined with precision loading and load experimentation should enable me to shoot tighter groups more consistently. My goal is to be able to consistently shoot .5″ 5-shot groups from this rifle off the bench rest.

Anything I’m missing here? Please comment!

Stay tuned!

3 thoughts on “AR-MPR: Phase II – Rifle Accurizing Plans”

  1. The PRS is a great stock for a target rifle and designed to fit virtually any shooter. That said, in my opinion most shooters that could be defined as plinkers will find it to be quite heavy. Shooters that prefer a bull barrel will probably appreciate it as it improves the balance of a rifle with a heavy barrel.

    1. +1 on this. Rock River Arms makes some of the tightest fitting receivers on the market.

      Gavin, have you heard of the receiver mod that in effect drills a hole in the lower receiver where the rear pin loop comes into the lower? People drill a small hole here and then install a rubber tipped Allen head set screw so that it contacts the upper receiver pin loop. This will also eliminate any slop between receivers.

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