Quote:
Originally Posted by edgarspencer
This may work very much against you because bore diameters varied greatly from early lifter guns and even later.
.729" may be considered the standard for 12 gauge but I know guns which measure over .750" and have never been touched.
You may err on the side of caution, and pass on a lovely gun that measures .740", assuming it had been honed eleven thous, you will loose out.
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Not necessarily, if I know the bore diameter of a certain era of manufacturing states a bore of .750, then my bore gauge will confirm this for me. I said that I do not have much use for a "wall thickness" gauge if I know the bore diameter of the manufacturer at differernt points in production history, such as the lifter gun you mentioned. If I am looking at an American 20 gauge shotgun, for example, and find the bore between .612 and say .618 or .619, and I know they don't vary by .030, I see no use in a wall gauge if no pitting exists. Besides, I wouldn't own pitted guns in the first place. And if I believe I am looking a special "back bored" barrel I can always measure the inside of the bore and outside barrel diameter to give me a general wall thickness. True, not as thorough and complete as a top end wall gauge, but close enough to assess the safety of the barrels. And my collecting is but a couple, few guns a year so my methods will prevail.
Bill