Looks like the old steel case carbine ammo. Other than steel cases, it will be non-corrosive and boxer primed. Yes, it's reloadable just like the brass stuff, but most people don't reload it. It can rust, it won't last as many loadings, and be sure to lube it good before sizing it.
What is the year on the headstamp? IIRC, steel case ammo was produced during the Korean war, but used for training only. I don't know how collectible it is, but you might check that angle out before shooting it up.