Quote:
Originally Posted by BLUEDOT37
Another S&W head scratcher... My 4013's label says 3-1/2" bbl. & my 4516-1's says 3-3/4" bbl. If you measure them from the bbl. tip to the breach end of the chamber, not the hood extension but just below it, both of them measures within 0.05" of 3-1/2". Of course the bbls. aren't really even that long either. If you measure from the chamber's shoulder, where the case mouth headspaces on, to the tip of the bbl., they're realistically 2-3/4" barrels.
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True enough, however the standard method of measuring a selfloader's barrel is from the breechface to the crown. Since there is usually a couple thousandths clearance between the breechface and the barrel hood, to get a truly accurate measurement you use a depth instrument. Insert the instrument down the bore and with the breech closed, measure directly against the breechface to the crown. This is the most accurate method.
However, to save time and the risk of scratching something we don't want scratched by sticking hardened steel things down the bore, we just measure hood to crown and that's usually good enough.
Cheers
Bill