I ran across this excellent thread in my desire to learn about a box of ammo I picked up this week and thought I would add some pics and details that are a bit different than those already posted in case someone else is trying to research this ammo in the future. This box is very similar to one that 29-1 had provided but has "Nickel Plated Shell" stamped on the box top in the first pic. The info on one of the sides is also different. The end flap (not pictured) has a lot number of K 3570T and the tuck in flap has a caution statement on the inside that states:

To insure the complete absence of corrosive fouling, before commencing the use of Staynless Ammunition, both new and old barrels should be flushed inside with a hot solution of washing soda or soap, or with boiling water and then wiped dry. We do not recommend the reloading of these shells.

A previous poster, I think on another thread, mentioned how much gunk was deposited from some of this earlier lead ammo.

Anyway, I thought it was cool enough to add to the bank of knowlege here.

Ed