12ga on 50 browning brass

In the past I have seen some 12ga .mil with brass cases and a 'cardboard' lid over the shot. .

at the gunshow last weekend I saw with I thought was an elephant gun cartridge but the guy with the ammo said it was 12 gauge something or other made with 50 browning brass.

I didn't get a chance to ask further question (like why?). Has anyone see or heard of such an animal and why was it developed.

It looked like a punt gun idea gone wrong to me.

thx

r

12 gague T-rex medication

I just read the first few pages of the link.

Oh MY,

Must have.

r