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					Originally Posted by  Andrew Sacco
					 
				 
				 
First question is, if "nominal" diameter is .662 (16g) and I get .665 or something, is that usually from boring out, or are Parkers pretty much consistent in their stated diameters? 
			
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 Bore diameters vary with maker and era.  I have a 1929 LC Smith 16 that measures .646 bores.  .650 +- was standard for their pre 1930 era 16 ga guns according to those who know. .662 afterward.    Similar thing applies to some Parkers.  Early 12 bores typically mic'd .750+- according to research done by AH while later 12's came down to .729.  Within those parameters, there is some small variation I have observed of 1-3 thousandths.  Outside of that, I would suspect honing, reaming, or backboring depending on the amount.  I would not worry about your .665 barrels.  Whether factory or honed, its not enough to make a difference IMHO.