I again slugged it with one of the 130 grain bullets that accompanied it. What is the best method to obtain the smallest diameter of the bore; i.e., where is is best to measure on the slugged bullet? I assume rotate it a full round?
It is widely - maybe generally - not recommeded that one attempt (!) to slug a barrel with the whole bullet. For two resons.
Firstly, the bearing surface would be too long; it is preferred to use a somewhat oversized round ball (so that only a deformed driving band remains flat around the circumference), or a rather short cylindrical body.
Secondly, a plug used for slugging must be dead soft. Antimony-hardened lead (as in cartridge rifle bullets) or gas checks are inappropriate.
Thirdly, but you will certainly have observed this, the barrel and the slug should be well oiled. I mention this only for completeness' sake.
Carcano
