there are companys still manufacturing all brass shells, they are not nessasarily military, you can still buy them, loaded with modern smokeless powder. Alot of these were used very early on, a hunter might only own 4 of these shells and would handload them in the feild(the old blackpower type) they would make their shot, reload, then stop and reload the shells from supplies carried with them. these real early shells were not just tossed away and would be a rare find, I think yours are probably early to mid 1900's, but without more ID marking they could be from a vast time range. I just bought some .410 all brass shells at the gun show the other day, they were made in russia, new manufacture, not old stuff. the #10 most likely stands for 10 gauge a popular chambering.I would go so far to say it is probably from the earlier 1900's as it is a 2 1/2 inch shell which was common then and not the more recent 2 3/4 inch shell that is still used today.
the smaller shell looks like it could be a early .44 long colt or similar, non-reloadable as there is no primer, really can't tell from the pic. don't see much of a rim though could be an old battery casing?