I made a cast of the forward part of the chamber today with the Cerrosafe. The neck has a slight taper. After cooling for an hour inside, just forward of the shoulder measured right at .3394 and then right at the end (forward of properly trimmed brass), it measures right at .338.
Wow, lots of room. No wonder I am having no problems with clearance. YMMV of course.
If I was making brass to sell commercially, I expect I would ream them to be sure, but for my use these will be fine as is. Even in a chamber with a .334 neck, a round that is .3326 (.0113 + .0128 + .3085 = .3326), or even .333 should be fine in any but an undersized chamber.
Other LC brass may be thicker, and that would definitely be pushing it. I wonder what other LC brass years measure out at after being converted.
The Cerrosafe description at Midway said:
It melts at a temperature just above M&M's
and that is pretty accurate. I melted a small portion of the Cerrosafe in an extra powder scale tray and poured it in the chamber through a cut off .06 case. Both held with Vise Grip pliers of course. The propane torch melted it it just like they said, nearly like M&Ms.
Oh yea, inside it was the cats supervising. Not much help actually.