With no information on the projectile it is hard to say. I believe it was foremost used as a rifle. The fact that it might have used a blank cartridge suggest to me that the exploding round may have had a shaft or long rod inserted in on top of the blank with the charge on the end, like a rocket on mortar. I also noticed the patch box latch, looks crude for a sporter. Just my thought nothing certain but very interesting. Its out there somewhere, ill keep digging. Rich