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Unread 08-29-2018, 08:01 AM   #37
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Quote:
Originally Posted by Dean Romig View Post
Just got around to measuring mine...

Right bore in beyond the 4” of choke taper is .620 and the left bore in beyond the 5 1/2” of choke taper is .622”

What does that tell you Frank?... if anything?

.
Dean, about 70% of the A H Fox 20 bore guns in my records have .615/616" bores, with a few outliers in the .617 to .620" diameter range. Many were measured using my current Baker bore mike which I've verified to be accurate, and others were done with two earlier mikes that had some +/- drift after being calibrated. Your bores are a little larger than typical but not that much so. Fox was buying barrel tubes from different specialty manufacturers and I'm sure the company ordered 20-gauge tubes within some range of tolerance on bore diameter. Fox also did the bore finish machining and on that note I've measured Fox guns with one bore (usually on the left) that was a few thou oversize relative to the opposite bore. It's my belief that such tubes were "reworked" by finishing oversize in order to remove machine tool marks such as a gouge or imperfection in the bore made during the first finish operation.

That 5-1/2" long choke is quite unusual in a Fox 20 bore and was probably done because of the very heavy choke constriction in the left tube. You might try patterning it some day with ducking size lead shot, maybe 4's or 5's.

frank
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