A new .40s&w brass test. 10 pieces

[kwatters]

I am amazed there are any left.

 

[downzero]

Load it until it cracks! Good stuff!

 

[mhs]

It would be interesting to do a test like this in a factory Glock barrel, rotating the brass to the same position each time. I'm guessing the failure mode would be a ruptured "Glock bulge", rather than a split neck. Might not be so fun for the tester.

 

[shibumiseeker]

It would be interesting to do a test like this in a factory Glock barrel, rotating the brass to the same position each time. I'm guessing the failure mode would be a ruptured "Glock bulge", rather than a split neck. Might not be so fun for the tester.

If you notice earlier posts, several of the pieces have failed in the middle of the brass, not on the neck. I'm running a similar test on a smaller scale with a Glock 20 with a .40 LWD barrel which is very tight, so we'll see what the failure mode there is.

If someone wanted to lend me a stock Glock .40 cal for a few weeks I'd be happy to run that test, but I don't own one and have no plans for it.

 

[SSGSAD]

Load it until it cracks! Good stuff!

This is what I do all the time, load 'em till they crack... Never waste brass.

 

[shibumiseeker]

After firing load 39, a nickel case developed a 2mm crack 4mm away from the neck, it was retired. After firing load 40, the last remaining nickel case had a crack in the middle. After firing load 47 a brass case looked to have a crack in the middle but no light shown through and it held air, so I loaded and fired again. After firing load 48 it had a 5mm crack in the middle, leaving 1 brass case left. I loaded and fired it 5 more times and had to conclude the test for the day as it got lost somewhere in the shooting shack, so it has had a total of 53 loadings and firings. If I find it I'll load it and shoot it until failure.

Thus far, while this was too small a statistical sample with too many uncontrolled variables to definitively say, it is suggestive that the regular brass has a SLIGHT edge over the nickel plated which is in line with my previous experiences. My guess is that the differences between manufacturers is far greater than the differences between plated and not. For what it's worth, most of the failure modes were cracks in the sides, not the mouth, but that's probably because I flared it almost none at all. Annealing every ten rounds probably would allow many more shootings, but is really not worth it unless it is truly TEOTWAWKI and every bit of brass is precious.

It's been fun, and I hope I find that last piece, I am curious to see how many more it will go. I'll post before and after pics in a few days when I get some free time after the holiday weekend.

 

[kwatters]

Thanks, this was enlightening and interesting to follow.

 

[shibumiseeker]

And it's over!

I found the brass this morning, it had hopped up on a shelf over the shooting bench.

After loading/firing #54 I noticed what looked to be a scratch on the side that may have been a split, 1-2mm long, but it held air and no light shined through. Loading #55 and the crack had gotten a hair bigger and was showing some sooting, but still no light and it may have leaked air, may not, it was hard to tell. After loading/firing #56 it had grown to 3mm and was definitely a crack as I could see light through it, so I retired it and concluded the test.

I don't have time or real inclination to run the distribution curve but if someone were so inclined it'd be interesting to see what shape the curve took.

 

[SSGSAD]

THAT report, is AWESOME !!!!! I really liked all the detail, and everything.
56 reloads... that is great !!!!!

 

[shibumiseeker]

THAT report, is AWESOME !!!!! I really liked all the detail, and everything.
56 reloads... that is great !!!!!

When I get back next week I'll weigh the brass and measure (though a spot check showed that they didn't grow more than .001" and get pics of them up before and after.

Anywho, glad folks enjoyed it! I have a better understanding of the failure mode for my loadings, it's always nice to have data.