In regards to the original question, if you're checking on a bolt action with a easily removable bolt, this is quite easily done. Insert bolt and close, insert rod (close to bore diameter works best) from muzzle end until it touches the bolt face. Mark at muzzle. Remove bolt, and pull you measuring rod back. Insert the bullet you wish to use into the chamber, pushing it all the way forward to rest against the lands with another rod or dowel. Slide your original rod in to touch the bullet, and mark it at the muzzle. Measure between your two marks (a small machinist rule works well for this) and that is your max coal for that cartridge and that bullet. I have used a stoney point before as well, the end result was almost identical. I would repeat with at least 3 bullets in that lot to give a statistically relevant measurement. FWIW. - dan
