Alpha .308 Torture Test: How Many Firings On A Single Piece Of Brass?

Just how many firings can you get out of a single piece of brass? We’ve already put Alpha Munitions OCD brass through the ringer, pushing .308 Win to .300 Win Mag levels. This time, we’re torture testing it again to find its breaking point!

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About the Experiment

This experiment is an extension of our previous OCD brass torture test. Once again, DO NOT TRY THIS.

We were able to obtain some incredible data in pushing .308 Winchester to the limit. We conducted this test as safely as possible with expert guidance, lots of math and data, along with quality materials.

Bruce Thom of BAT Machine has done destructive testing on his actions before, so he knew exactly what to look for.

We fired Berger 215 grain hybrid target bullets, incrementally increasing the charge weight over time. We had no brass failures and did not blow any primers, though we did observe some cratering near the end of the test. The question remains, how many max-load firings can a single piece of .308 OCD brass take?

About the Brass

This experiment wouldn’t have been possible with any other brass. The details of brass, the reloading process, and a rifle’s chamber all have to come together for safe, proper firing.

Alpha Munitions offers their American-made OCD — Optimized Case Design — brass in a number of cartridges. This brass is centered around three fundamentals: consistency, strength, and stability, and is built to last. Alpha Munitions says “OCD brass is the strongest, most durable rifle brass ever produced” and “plastically deforms less than competitors at identical loads” in testing. These quality cases come by the 100-count in plastic cases ideal for protection and storage of loaded ammunition.

From Alpha Munitions:

– Optimized Case Design with Optimized Case Head Technology

– 100 count boxes ship in custom Alpha Munitions plastic cases with perforated bi-layer foam for protection of cases and loaded ammunition

– 500 count orders ship in custom cardboard boxes with dividers.

While the specific metallurgy and manufacturing process of OCD brass are trade secrets, Alpha Munitions doesn’t hide how they check their brass. Each case is inspected on a custom machine with state of the art sensors for consistency. This process includes 10,000 images of the neck and shoulder; 3D mapping of every part (accurate within 0.2 microns); 10 key dimensions checked (accurate to +/-2 microns); and the flash-hole, head-stamp and primer pocket checked with a 21 megapixel camera. This isn’t a common practice – most brass is checked only for major defects.

The Load and Process

I didn’t have enough 215 grain Bergers remaining for this test, so I switched to Hornady 212 grain ELD-X bullets.

I consulted Hodgdon’s Reloading Data Center and confirmed a max load of 41.3 grains of Varget. (Always consult OEM sources for load data and start before max load!)

I loaded this in Alpha Munitions .308 Winchester small rifle primer OCD brass with Federal small rifle primers. (Small rifle primers tend to hold up better than large rifle primers.)

I photographed the brass after each firing and followed the same procedure:

Size/Deprime
Prime
Charge
Seat Bullet
Fire in Rifle

I did not anneal during this process, but used the same exact case.

I sized and deprimed this case on the Area 419 Zero Press with an M-series die and primed it using the Primal Rights Competition Primer Seater.

I was careful not to overwork the brass.

Next, I dropped a max charge from a Hornady Lock-N-Load bench powder measure and seated the bullet back on the Zero press with a Redding competition seater die.

About the Rifle

I am using the same rifle I used in my previous tests: a strong BAT Igniter action with a 1:9 24” Ballistic Advantage barrel in a Foundation Centurion stock.

I chambered this rifle with a 0.096” freebore with an Alpha Legacy reamer on my Precision Matthews lathe.

I also added an EC Tuner brake, Hawkins Precision M5 DBM bottom metal and a Leupold Mark 5HD 5-25×56 scope.

Results

In addition to photographing the case after each firing, I also recorded myself shooting.

Watch the full video to see the progression. Primers remained intact for all 47 shots – the very last shot displayed slight cratering.

New Alpha Munitions .308 Primer Pocket vs 47th Fired Primer Pocket

The brass held up for 47 firings, at which point it developed a major split in the case neck.

I didn’t even notice it until reviewing the photography — I initially thought it was just some carbon.

Upon further investigation, I learned the crack began developing around shot 31, though with no marked loss in velocity.

One thing I forgot about was trimming. I’ve been shooting so many rifle cartridges that don’t require trimming and I’ve never loaded the same piece of brass 47 times, so it slipped my mind. I trimmed the brass for the first time after shot 30 when I noticed it didn’t chamber as easily. It measured 2.037”; factory spec was 2.007”. I trimmed it to 2.005”. The brass measured 2.016” at shot 47. On average, this brass stretched about 0.001” per firing, which is a very small amount!

It was also especially interesting to compare the velocity data. The average velocity was 2,497.9 fps, exceeding Hodgdon’s 2,399 fps prediction. I observed a 7.5 SD and 37.4 ES. Much of the extreme spread occurred between shots 1 and 2. (The chronograph missed one of the 47 shots, so we have 46 data points.) Overall the chart looked very stable, but there were a number of fluctuations between 2470 fps and 2520 fps.

Conclusion

Alpha Munitions OCD brass is incredibly stable. Not only did it hold up for 47 firings, but it also didn’t stretch much at all.

New Alpha Munitions OCD Brass Next to 47th Fired OCD Brass

Annealing would have likely greatly extended the life of the brass. I’m currently using the AMP Mark II DB. It is incredibly consistent and determines the optimal settings for your piece of brass. Including that in a future test could be intriguing.

I did not shoot for precision in this experiment, but it’s important to note that I’ve observed impressive results with Alpha Munitions in the past. The best group I have ever fired came from my 6mm Dasher (chambered with an Alpha Munitions reamer) using brand-new Alpha Munitions brass.