I have a question about the use of the shoulder stock.
Is there any history of the shoulder stock being used in the war and how common was it?
The Army did do some testing with the Colt Dragoon and shoulder stocks. I believe they took delivery of 100 revolvers in the early 1850's. For a solider it's more kit to carry. It does not increase the range of the revolver although it can increase accuracy at longer range. They were probably not very popular with line troops.
When using a shoulder stock or a revolving carbine you must be aware of off hand placement. Considerable amounts of flame comes from the barrel gap and well burn and even cut through flesh if your hand or arm is in close proximity.