Chief,
I know a fellow who bought a Colt revolving rifle with a guard beneath the cylinder for the shooter's left hand. Instead of resting the weapon on the left palm, the shooter would rest the weapon on his index finger near the last knuckle joint. The hand was held perpendicular to the rifle. There was a front & back section to the guard to steady the left hand.

There'd be less of a danger if it chain fired with that setup.