bud , i did a little research on this and it sounds like a " european garden shotgun " or a " 9mm flobert rifle/shotgun "
dixie gun works has 9mm rimfire shotshells made by fiocchi of italy , they're 1 i/2" and made of brass. get the rifle from your grandpa and try contacting them and decribe the rifle to them , all markings and numbers and any engravings that are on it and they might be able to help you positively identify what she really is , and might be able to help you with shells
thier address is
www.dixiegunworks.com
another option on identifying the gun and caliber would be to contact the following companies
1. old western scrounger , in montaque , california 530-459-5445
2. huntington die specialists in oroville , california 916-534-1210
try all three if possible but , definitely get the gun identified
