Reader Thundervoice writes:
I want to shoot as well as I can, if for no other reason than I’m detail-oriented and the engineer in me is always looking to make a process or system better. So I was never particularly satisfied with the accuracy of my MSR. It only produces about 2 MOA with the Federal factory ammunition I typically buy at Wal-Mart. Not bad, but nothing to write home about.
I once saw a gentleman at the range with a box of hand loaded ammo that varied in 0.2 grain increments and the results were my first indication of how much difference just a little bit of powder can make in downrange accuracy. Seeing that made me want to experiment on my own with powders and loads to get the most out of my MSR. So I did.
First, the equipment. For this experiment, I used a Stag Model 3T upper with a 16-inch barrel that has a 1:9 twist. The upper was matched with a lower I built that included a James Madison Tactical Saber single-stage trigger I selected based on a TTAG review. The buttstock is a Magpul ACS, which provides a better cheek weld than the mil-spec buttstock that came with the rifle.
The scope was a Bushnell AR Optics FFP Illuminated BTR-1 BDC Reticle AR-223 Riflescope with Target Turrets and Throw Down PCL, 1-4x 24mm. I supported the rifle barrel on a Caldwell Handy Rest Shooting Rest. The targets were 100 yards downrange. I did the experiment on a day when the temperature was 91 degrees and the humidity was 59 percent.
The basic concept of my load experiment was to create four loads for each of five powders and determine the resulting impact on accuracy. I started near the minimum load for each powder and increased the load by 0.5 grains, resulting in a total spread of two grains.
I used the same bullet for all of the loads, the X-Treme 223, 55 grain, full metal jacket. These bullets have a ballistic coefficient of 0.243 and are intended for target shooting, plinking, and varmint hunting. The five powders I used were all Hodgdon: Benchmark, CFE 223, H322, H4198, and Varget. Load data for all but the Varget were taken from the Hodgdon website.
I used the Lyman 49th Edition Reloading Manual for Varget, which had a starting load of 25.0 grains instead of the 25.5 grains shown on the Hodgdon site. For all five powders, the upper end load for my experiment was at or slightly below the maximum load.
As a control, I also included the Federal .223 55 grain FMJ factory ammunition (100 round box packaged exclusively for Wal-Mart) that I typically use for target shooting. The cases I used for reloading were mixed .223 brass recovered from previous shooting sessions (no military brass).
I shot the loads in the following order: Benchmark, Varget, H322, CFE223, H4198, and Federal factory. After shooting the first two powders (Benchmark and Varget), I adjusted my scope to bring the point of impact down and to the right. I started with the lowest load in each powder, working my way up the load increments. For each load, I fired five shots.
The table indicates the maximum spread of five shots and the spread for the four tightest shots (assuming one flyer) for each powder and load. Powders are listed by burn rate, with the fastest burning powder at the top of the table. The burn rate values are from the Hodgdon website where #1 is fastest powder.
The maximum load is shown for information purposes only, as the maximum wasn’t used for any of the powders. For two of the loads, one of the five shots was off-target and the five-shot spread for these loads is indicated as >5 inches. Load values are in grains of powder. All of the spread measurements are in inches.
The photos illustrate the results for each of the powders and the Federal factory load that I typically shoot. The target rings are at 0.5 inch radius increments with outside circle having a diameter of 3 inches.
Overall, I learned several important lessons from this little experiment. The results indicate that both the powder and the load can make a difference in the accuracy of a rifle. My goal was to see if I could find a powder and load that would allow me to shoot a dime-sized group (~0.7 in) at 100 yards with my rifle.
If I base my results on the 4-shot group size, the H332, Varget, and CFE223 all provided that level of accuracy. Only the H322 powder provided a dime-sized 5-shot group. The most accurate load for each powder was one of the middle loads, not the smallest or largest used in the experiment.
There are some things I should have done differently. Given the limited number of shots for each powder (5), I should have used a more stable platform or rest for the rifle to minimize the impact of the shooter on the results. The differences between the 4- and 5-shot group sizes are likely due to the shooter more than the powder and/or load.
It would have been more informative if I had been able to chronograph the loads during the experiment. Unfortunately, I don’t have a chronograph and don’t know any fellow shooters that have one they would loan to me. I also should have sorted by brass and used the same brass for all of the loads.
I probably should have done the experiment over several days instead of all on one day. By the time I got to the last powder (H4198), I was starting to get tired and that may have affected the outcome for that powder. The H4198 powder had the largest groups, which may be due to being last in the order.
I plan to repeat this experiment at some point in the future and to include a different upper with a longer barrel and tighter twist rate as a comparison. Next time, I’ll implement some of the lessons learned and see if the results of the initial experiment are repeatable.
The bottom line for me is that I can improve the accuracy of my rifle by custom tailoring the loads I put through the barrel. If you don’t reload and want to improve your rifle’s accuracy, you may want to try some different types of factory ammunition to see which will provide you the best accuracy.