Awesome finds!!! You might find this PDF interesting. http://chab-belgium.com/pdf/english/Exploding bullets.pdf According to that there were only 33,350 in 1863. It does not say if that was the total number that were issued or not.
Yes buddy I have a little spot that they turn up at. There was a electric fence there & I couldn't get within 20' of it. Now its gone but the grass is high but I managed to pull them out ofva ground hog hole pilings. The one wasn't but 2" & right next to it was one about 8" deep. I went over the one & I was like no way in a ground hog tailing pile. I dug it & like wow you have to be kidding. I dug two there years ago so I went back & plan on going back again sooner or later.