Thank you for the reply. I can be dumber than a rock. Is this lip very pronounced? It appears the forward end is larger/sloped?? than the extractor side. My tools are still in storage, but I probably can borrow a micrometer from someone. Any further description or if you have one perhaps a photo?? Either way, Thanks.
You can just post some images looking down into the Cylinder chambers.
If you have some .38 Special laying around, you can just see how the Bullet itself fits in the Muzzle end of the Barrel.
I do not remember what year they went from the outside Lube to the inside Lube or how soon after they reduced the Barrel Bore diameter.
The earlier outside Lube Bullet, the Bullet itself was the same diameter as the Cartidge Case, and the Barrel Bore Diameter was also.
But, only the late Cylinder had a 'step' which registered for .38 Special length ( far as I know ) rather than registering for .38 LC length...and the Revolvers at that point were warranted for .38 Special, even though they were still technically .38 LC and of course continuous with the .38 LC production of their Model designation.