Hmmm...
The point of a Sawn-off Shotgun is to trade accuracy for power. (Not that it was accurate to begin with...) So, is this a lesser accurate but moar powerful version of the Milkor?
Grenade won't be any more powerful if the barrel was longer.
So it's just a less-accurate, same-damage, grenade launcher.
This would be better off using flechette rounds instead of grenades.
Poll