Bobby not being able to hit the broad side of a barn with The Colt is V realistic. The rifling in the barrel was likely fucked up something fierce when it was shoved into that big stone lock. Without proper rifling, you really can't hit the broad side of a barn because the bullet won't come out right. Rifling in the barrel gives the bullet a spin as it comes out. It makes it more accurate.
I will type of those nineteen pages of firearms notes soon, really I will.