Hello Big Redneck
Welcome on your first postings
Great gun,
Yes ammo can be made for your drilling,
First what is necessary is a chamber casting and bore
measurement.

Have fun here
http://www.shotguns.se/html/germany_1890-1945.html

Cerrosafe should be use for the chamber casting

https://www.youtube.com/watch?v=2d5DA4_OcuE

http://www.midwayusa.com/product/462291/cerrosafe-chamber-casting-alloy-1-2-lb

Again, Welcome
Mike

p.s. if you have a dial indicator, could you give us the approximate internal barrel diameter?

http://www.rstshells.com/store/m/3-16-Gauge.aspx