Starline 6.5 Creedmoor SMALL RIFLE PRIMER Brass Endurance Testing- firing the same cases 12 times

This is my second “brass endurance testing” post. Part 1, Starline 6.5 Creedmoor Brass Endurance Testing- firing the same cases 15 times, gave an overview of how and why I conducted the test. I suggest reading it prior to this post.

In Starline 6.5 Creedmoor Brass Endurance Testing- firing the same cases 15 times I was really impressed with the quality of the large rifle primer Starline brass and the number of firings I was able to obtain from it. In this post, I conducted the same test with the small rifle primer version of the Starline brass.

To recap, I randomly selected 5 cases from a large box of bulk packaged brass and headed to the range with a set of hand dies to load the same 40.8 grains of H4350 over a CCI primer (CCI 200 for LR brass and CCI 400 SR brass) with a 142 GR Sierra MatchKing. I’d fire five-shot groups prone, from a bipod with rear bag until the brass cases failed or the cases were unable to chamber. I only neck sized the brass. Muzzle velocity was recorded with a MagnetoSpeed Barrel Mounted Ballistic Chronograph. I used a set of Rite in the Rain Storm Site Targets at 100 yards.

Before we get to work, let’s recap the disclaimer below.

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. Rifleshooter.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.

Test gun

I’ve been using my custom Remington 700 a lot lately, I love this thing. I built it with parts from Brownells, including:

I’m running this in an MDT ESS Chassis System (Click here to learn more about the ESS).

Results:

Muzzle velocity ranged from 2,750 to 2,788 ft/sec with an average of 2,775 ft/sec. Standard deviation ranged from 3.0 to 24.8 ft/sec with an average of 12.5 ft/sec. Five-shot group sizes at 100 yards ranged from .556″ (.531 MOA) to 1.001″ (.956 MOA) with an average group size of .724″ (.691 MOA). I was only able to fire the set of cases 12 times (11XF brass). At this point, I was unable to chamber them. The primer pockets were still tight throughout the test.

You’ll notice a trend in increasing muzzle velocity during the course of the test.

I happened to conduct this test when it was 81F outside, this was the same ambient temperature as the test I conducted with the large rifle primer Starline brass. I went ahead and graphed the set of data from the small rifle primer brass against the data from the first 12 firings of the large rifle primer brass to see how they compared. You’ll note both cases trend up in muzzle velocity as the number of firings increase.

Closing

In my gun, with this load, the Large Rifle Primer Starline Brass seemed to perform better than the Small Rifle Primer Starline brass, however, the SR brass did have a slightly lower average SD as well as slightly higher average MV. I’m not sure this was a function of primer size or another variable. I will say that even though the LR brass outperformed the SR brass, I’m still fairly impressed with both, especially for the price. The small rifle primer brass averaged .691 MOA over 12 groups, that’s good!

I’ll be repeating this experiment with a couple of other brands of brass and reporting back.

You can learn more about Starline Brass here, or purchase it at Brownells.

I’ve also opened a retail store and gunsmithing operation on Long Island, NY. If you want to check it out see www.782guns.com or visit our Facebook page, here.