Odd 9mm case

[DIY-Pete]

At Bullseye League last night one of the guys asked me about a 9mm case he found in the brass bin. It is an odd duck that's for sure and I had nothing to offer in the way of information. That said any information about the case construction and the reason for it would fill in the curiosity gap. We decided that these would not be reloaded by us.

The wall thickness is .0115 at the top and .045 at the step.

Thanks
Pete

 

[straight-shooter]

I've read that the step is to prevent bullet set back. It's said to be safe to reload but if the bullet is seated to deep it will damage the case.

 

[Blue68f100]

They are safe to load. You just have to be aware of your bullet seating depth. As always start low and work up. I have several 100 i've collected over the years. When I know I can't retrieve my brass I will use them.....

 

[rsrocket1]

They will work fine with mid range loads although the velocities will be a bit higher because of the smaller case capacity and higher pressures. Just don't load them with max loads. The good thing is that the case head is also thicker so it will likely withstand a higher pressure than normal.
Cutaway pictures of the brass compared to "normal" brass from Castboolits thread

 

[wally]

Obviously ammo makers are starting to get worried about lawsuits from KaBoom's caused by bullet setback. As long as your bullet doesn't protrude into the case beyond the "step" and you are not pushing maximum loads I'd not hesitate to reload them. I have reloaded a fair number of the IMI cases with the "step" without issue.

 

[TRX]

Some guns have a steep enough ramp angle that you often get some amount of setback every time you run a round into the chamber. My 1911 will do that with most commercial ammunition; when I give it its weekly cleaning I put the previously-chambered round in a range bucket and put a new fresh round in the magazine.

 

[Walkalong]

The good thing is that the case head is also thicker so it will likely withstand a higher pressure than normal.

Great pics, but if you look, the case wall isn't any thicker at the web, it just stays thicker up higher to make the ledge. Those case heads are not going to stand any more pressure than a normal one. The web is thicker, but not the case wall where it meets the web, which is the weak spot.

 

[wally]

My 1911 will do that with most commercial ammunition

You need better mags unless its a ramped barrel "widebody" gun. The single stack 1911 is a controlled feed design and the mag spring is supposed to push the round up under the extractor before it hits anything -- its more of a clearance cut in the frame than a feed ramp. The Para P-14 type guns do need a feed ramp and its probably why their reliability is usually less than stellar. I often shoot my RIA widebody "ramped" 1911 along with my RIA single stack and its obvious by the shiny line on the ramp that the rounds are pushing on it whereas the single stack the "ramp" is pretty much uniformly dirty because noting much is ever touching it.

 

[JeffG]

Learn something new every day....

 

[mstreddy]

If that is a silver looking case it might be steel. Run a magnet over it to check. I've run into some of those headstamps and some are steel.

 

[DIY-Pete]

Thanks for the replies. Thats a lot of extra material and lost case volume to prevent setback. I'm a little foggy on cold medicine this morning so I won't attempt the math but it looks like 10 to 20% lost case volume. I don't reload at max but I am a long ways from powder puff loads. I like my practice rounds to closely replicate my carry ammo.

Correct me if i'm wrong but with a properly constructed round it takes a good bit of force to induce even a small amount of setback. I generally cycle a dummy round or two through my gun a couple times verify that I am getting very little setback before I call my reload setup good.

Pete

 

[Dill]

I found one similar to that while doing my last batch of 9mm, it was a Freedom Munitions case. It was only one case so I tossed it into my scrap bin.

 

[ATLDave]

This stepped brass is getting a bad reputation among USPSA shooters/reloaders. It is known for separating at the ridge/rim (speculation is that the right angles involved create a stress riser). Many malfuctions and jams that cannot be swifty cleared are reported and photographed. I would steer clear.

 

[Blue68f100]

I did a volume test on them when I first ran into them. If I recall the were the same volume as a std 9mm case I used. Now this was close to 10 yrs ago, I did the test. As long as you start at min and workup there is no problem.

 

[macgrumpy]

Great pics, but if you look, the case wall isn't any thicker at the web, it just stays thicker up higher to make the ledge. Those case heads are not going to stand any more pressure than a normal one. The web is thicker, but not the case wall where it meets the web, which is the weak spot.

When people say that the web is thicker I assume that they are referring to the head area of the case, it is thicker there with a resulting long flash hole. I assume that setback was the problem that they were trying to fix and they didn't make the cases with reloaders in mind.

 

[Jesse Heywood]

Wouldn't these eliminate the Glock bulge?

 

[macgrumpy]

I'm sure that it would help avoid the Glock bulge, maybe that's why they designed the case this way. Depending on how you define the web you could argue that the web isn't any thicker but SAAMI and several other sources state that the web is the bottom part of the case between the primer pocket and the inside of the case so by that definition the web is thicker. But even if you want to include the case walls as part of the web then you have to admit that the web is thicker up higher and that would increase the strength where the Glock bulge occurs.

 

[Walkalong]

I assume that setback was the problem that they were trying to fix and they didn't make the cases with reloaders in mind.

Agreed.