it looks like a bore gun cartridge

the french tabatiere snider used a 38mm longpaper case with brass base very simlar to 12 ga shotgun brass. this example here was sold in france, made with a once fired 12 ga shell.

it holds a undersized minie bullet like the original cartridge

this cartridge looks like an old 12/40 bullet cartridge with a homemade cutting paper shell. it can safely fired in such an old hunting rifle but is the biggest of all snyder conversion cartridges.

finaly one guy on gunbords order a die set for 12 magtech brass from CH4D http://forums.gunboards.com/showthread.php?t=34615&highlight=tabatiere