Boyd's Prairie Hunter Stock Accuracy Test: Thompson Center Compass .308 Winchester Load Compilation and Shooting Groups Part 5

Preface

This is part of a written compilation of a series of accuracy testing with the Thompson Center Compass bolt-action rifle, chambered in .308 Winchester, which will include load development using numerous different components and the installation and glass-bedding of a Boyd’s Prairie Hunter stock. We will establish 3 different loads using different components (each with it’s own post and video), then we will use those loads to get a baseline of accuracy with the stock that comes on the factory rifle. Once we do that, we will test those same 3 loads with the Boyd’s stock installed. Last, we’ll glass-bed the stock and test those same 3 loads again to see how the accuracy changes throughout each step of the process. In theory, we should see a linear increase in accuracy, but this is going to be a way to see first-hand if that will actually hold true.

This test will be the portion where we take the 3 best loads compiled from previous batches of load development on this rifle and shoot several groups with each load and average them out to get a baseline of accuracy with the Boyd’s Prairie Hunter laminated wood stock. The previous test was of the same format, but the previous test was to get a baseline of accuracy on the plastic stock that came installed on the rifle from the factory. Those results can be found here.

The Specifics

Recently, we had done some accuracy testing/load development with 3 different load combinations including two kinds of powder, three kinds of bullets, three kinds of brass, and one primer. The best “accuracy load” from each day of load development is the load that gets to move on to this portion of the testing, as well as the rest of the shooting for this process.

So, now that we have our best loads compiled, which will be listed below for reference, we are going to shoot 20 rounds of each load (in four 5-shot groups) and average out the groups to get the baseline accuracy for each particular load with 3 variations of stock installments. As stated earlier, this test has already been conducted on the plastic stock, and today we are going to be conducting the same test with the Boyd’s Prairie Hunter Stock installed. Once this test is concluded, the same test will be ran with the Boyd’s Prairie Hunter Stock glass-bedded to the rifle action using Brownell’s Acraglass kit.

WARNING: The loads shown are for informational purposes only. They are only safe in the rifle shown and may not be safe in yours. Consult appropriate load manuals prior to developing your own handloads. Risencitizen.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

Components Used/Loads Chosen

Load 1

Brass- PPU/PRVI Partizan
Bullet- Hornady 168g Z-Max
Powder- Varget 42.5g
Primer- CCI Large Rifle #200
Seating Depth- 2.800″

Load 2

Brass- Winchester
Bullet- Hornady 150g Hornady soft-point (flat base)
Powder- Varget 45.5g
Primer- CCI Large Rifle #200
Seating Depth- To cannelure

Load 3

Brass- Starline .308 Large Rifle Primer
Bullet- Sierra Palma 155g Matchking Hollow Point Boat-Tail
Powder- IMR 4895 43.5g
Primer- CCI Large Rifle #200
Seating Depth- 2.775″

Loading Process/Case Prep

All of the loading/case prep has already been covered in the previous posts, so I won’t go in-depth on what we did for each load, but the same equipment was used to load all the rounds with the exclusion of the PRVI/PPU brass. All the brass was neck-sized except for the PPU because all the PPU brass that I have used will stick in the chamber if it isn’t full-length resized, and this brass is no exception.

Here are links to the previous posts for those that would like to see how each batch of rounds was loaded or compare this test to the last test…

Part 1: PPU Brass

Part 2: Winchester Brass

Part 3: Starline Brass

Part 4: Plastic Stock Accuracy Test

Shooting Process

Up to this point, all of the shooting has been conducted in the same fashion. This test will maintain the same basis of fundamentals, but I will be shooting one load per target in four 5-shot groups. A Champion Redfield style paper target is placed at 100 yards and all shots are fired from the prone using a bipod and a rear sandbag. All rounds are magazine fed, time is alloted for barrel cool-down between shot strings, and all shot groups are fired on the same day to keep environmental conditions as consistent as possible.

Results

Below are pictures of the targets, in sequential of the loads listed above, after all the groups were fired and measured in inches using calipers (measuring from edge to edge and subtracting the bullet diameter). Included is a video of me discussing the results, but not of the actual shooting as I was down a camera at the time.