If you are referring to shooting vintage, old military .30-40 Krag ammo in your Krags, yes, it should be fine. Many of us have shot old military surplus .30-40 ammo in our krags without any trouble. The old loads are fine as far as ballistics and pressures for the Krag action.

But, this depends on a couple things. First, of course, your Krag needs to be functional and without any mechanical issues such as a cracked bolt or damaged chamber or bore. Many old Krags are in great shape but there are a fe out there that shouldn't be shot. Just check it out or have it inspected properly.

The other factor that limits use of old ammo of any sort, especially old Krag ammo, is neck splitting. Many old cases have split necks or the necks of the old brass are weak and will split when shot. This usually isn't a problem as far as safety if it happens but it is not, generally, safe to be shooting old weak rounds. Check them carefully. If they are old re-loads, I would just pull the bullets and dump the powder, check the cases well, and re-load. Keep in mind that old ammo may have corrosive primers and require immediate cleaning of the rifle chamber and bolt and bore after shooting.

I have shot many old rounds in some of my Krags without problems. I do have many with split necks I have found and discarded and I clean them well after using old ammo.

I wouldn't shoot some old ammo because some of the real old stuff is collectible, especially if you have the colorful boxes with them!

Good luck and keep us informed.

---