I'm currently trying to figure out how to properly mod a more efficient digger. At the moment I've set the normal "stats" higher for the heavy digger, namely the firerate. I've also inserted a custom ammo round. The only problem is, the diggers abilities (digging through rocks) are dependent on the mass of the ammo, but if you have the mass set to anything above 0.01 it shoots you around like a second jetpack. 0.01 really only makes for an effective lawnmower. Any help? Is there a specific setting for "pushing" the actor back every time it fires?

The simplest answer: Mass isn't the only variable that lets you dig better. A high Sharpness can cut through anything like butter.