Time to ask the community what this rifle brass was altered to shoot in. I know it's one of those geez.....could be anything and if there is no answer to be found so be it, no biggy, they were free. Base is stamped 30-40 krag. Rim has been turned down to .477 or .478 with a case length of 2.257 or 2.258 and a base of .4205, now these are measurments from fired shells. The case mouth measurement averages .367 to .368.
Here are images: