[QUOTE=dfariswheel;1065399]The forcing cone is a revolver "thing".[UOTE]

No it isn't.
Shotguns have a forcing cone.Rifles and Auto pistols have a throat to ease the bullets entry into the rifling which is no different than a forcing cone.The only difference with a revolver is the jump from the cylinder to the barrel which is why they have a 9 1/2,11 and a 18 degree entry angle.

Ken