Aluminum versus Steel Case?


April 11, 2008, 10:43 PM
I'm considering stocking up on Wolf Steel Case 9mm. I will be shooting it in a Glock 19, CZ-75 SP-01, and Kel-Tec Sub2000. The Kel-Tec specifically prohibits aluminum cased ammunition. Aluminum is much softer than steel but what is the difference between these two choices for casing? I know they are both cheaper than brass of course. Is steel case OK to shoot in these guns?

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April 11, 2008, 11:18 PM
Bill St. Clair ( says both work for him, but admits that aluminum is against the rules.
My guess is, even if steel case doesn't work reliably, it won't damage the weapon, or they'd warn against it in their literature. I intend to try just the thing after I scrape together enough for a SUB 2000.

April 11, 2008, 11:29 PM
How come some cheap ammo uses steel case and some uses aluminum case? What are the advantages/disadvantages?

evan price
April 12, 2008, 01:11 AM
The KT carbine has a very vigorous extraction and it will tear the rims off of aluminum cases. Steel cases, OK.
But for my money, you can get brass cased ammo as cheap as steel so why not use brass?

April 12, 2008, 01:18 AM
That is a very good question. Frank C. Barnes deals with it obliquely in Cartridges of the World. He doesn't state outright, but it looks like the advantages of aluminum are that it is much lighter and cheaper than brass, while steel is just cheaper. (Both have the disadvantage of being difficult or impossible to reload.) He dismisses the notion that case strength is an important factor, noting that aluminum is in use in 20mm and 30mm autocannon ammunition - when your weapon burns 3000 or 6000 rounds per minute, weight is at a serious premium, and when your cartridges are that large, material cost is as well.

I suspect that the difference for us Kel-Tec fanciers has to do with chamber pressure, and how the cartridge material behaves under heat and stress. Aluminum cases seem to work fine in most semi-automatic pistols; with the 9mm Luger and .40 S&W stuff we're talking about, those are all locked-breech weapons with very few exceptions. The big SUB 2000 can be built with an unlocked breech (straight blowback, similar to a lot of .32-caliber pistols or 9mm submachineguns), which apparently works fine for ordinary (expensive, reloadable) brass cartridges but not so much for aluminum.

"Steel and aluminum cases do not resize and reform as completely as brass" says Barnes.

April 12, 2008, 09:05 AM
I only use brass,why use the rest to save a few bucks,it isn't worth it.

April 12, 2008, 12:33 PM
A lot of you guys are saying to "just use brass" because the price difference isn't very great. I have almost 1000 cartridges of Winchester White Box 9mm brass from the days of cheap Wal-Mart deals.

Old Wal-Mart WWB 9mm Brass: $13.99(?)/100, ~14 cents/round
New Wal-Mart WWB 9mm Brass: $18.99(?)/100, ~19 cents/round
Wolf Steel Case 9mm: $169/1000 shipped, ~17 cents/round'

My recollections on Wal-Mart prices are probably conservative. Are there some other competitive deals these days on brass 9mm?

April 12, 2008, 12:52 PM
I think the warning about using aluminum case ammo in the SUB2000 stems from the fact that it is a blow-back action.

Aluminum cases are more prone to sudden failure if the bolt opens before pressure has dropped sufficiently. Or if the gun fires slightly out of battery due to dirt & crud build-up.

There were big problems with open-bolt submachine-guns a few years ago.


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