A Russian (of course) has done a fairly good job of producing a very simple, acc

A Russian (of course) has done a fairly good job of producing a very simple, accurate, explosive 12ga round. His prototype (which is available) stores legal amounts of explosive, but the design can be extended to expand that amount, and house higher explosives. The design is quite simple, very accurate via a rifled choke, and is ‘set off’ by a simple .22 blank or .22 nail gun load.

The traditional example used by Russians in wwii as sniper ammo was extremely effective but difficult to manufacture – although the rounds are still avaiilable surplus they are rare and still work.

The other model is the he-grenades that require fairly sophisticated (expensive) mechanisms (unlock via centripetal force on firing, explode via impact on internal pin and primer) in order to prevent accidental explosion.

The HE grenades are largely shrapnel producers. The explosive rounds are for causing even more injury -even behind walls.

My dream is a 9mm to 10mm semi auto over, and a 12ga single shot explosive and fragmenting lower, and two triggers.

Why? Just ’cause sometimes you need to ‘make a big impression’.