Found some aluminum 45-70 cases F 1-92 headstamp

So I came across some 45-70 cases that appeared to be aluminum, which I thought was strange. I’d never seen an aluminum case in this caliber so I grabbed them. Primers were still intact too, they were apparently never fired but are empty with no projectile.

They are definitely non-ferrous, a super strong magnet has no effect whatsoever on them. The headstamp is in 3 sections - F @ 12o’clock, 92 @ 4 and 1 at 8 o’clock. Primer is rounded type.

Researching these in History of Modern Military Small Arms Ammo book, they appear to be an experimental cartridge made in early 1892 by Frankfort arsenal. The book says something like 250 were made, so it would seem that survivors would be quite scarce. Has anyone seen one of these before? Could they be some of these experimental cartridges??


More likely they are tinned brass.

Yes tinned brass standard on Frankford Arsenal production of the period.

They sound different than typical brass and only weigh between 11.1 - 11.3 grams.

So take a knife or a file to the case and see what lies beneath the surface!
If there is colour change it’s tinned brass if the colour stays the same it’s aluminium.

Did they have the tecnology to deep draw aluminium in the 1890’s?

PS: I just weighed a W-W 45-70 brass case and it clocked in right at 11,1grams

100% tinned bras , 1892 year , Photo for comparison:



Hi John,

Here is an example of the box for these cartridges: This one is dated May 7, 1891:




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Thanks all, great info! I didn’t want to reload and shoot these if they were some kind of collectible variety but it sounds like they’re not all that scarce?

I wouldn’t load them. They are old and, more than likely, of the balloon headed configuration. Why take the chance of a head separation. Plus, they are NPEs, and will only be new once if they are loaded and fired. The primers probably won’t fire anyway.

The primers are definitely not going to fire, I already made them inert. I don’t shoot corrosive primers anymore, not worth the bother. I just pop them out and reprime when I come across any.

Good point about being new once, I only wish I had the projectiles but someone pulled them before I got the shells.