Old ammo, judging by that hollowpoint bullet.  My grandma kept a live SL-43 50BMG round that my uncle brought from gunnery school in her nick knack cabinet for nigh 60yrs.  Uncle was a B-24 ball turret gunner.  I pulled it down and found that the brass had pulled all the moisture out of the powder, the inside of the case was green, the powder was starting to turn to dust.  I used some of the powder in 6.5 Japanese loads, it wasn't burning at no 4831 speed!