Just looking through the bore from the breech, all the older, standard cones "look" very short and abrupt. My Skeet's bore mike isn't large enough to measure the actual end of the chamber on a 12 ga. It hits metal part-way into the forcing cone. So I have to measure the actual chamber length with my very sophisticated tool, made from a stainless steel ruler, and calculate cone length with a combination of that information and where my bore mike determines the cone stops and bore begins. Most of the ones I've measured are in the 1/2" to 5/8" area, even though to look at them, they might appear to be much shorter than that. To say there is "no, or "practically no" forcing cones implies the chamber end and bore are the same size, as 2-P suggested.
