Seems to me like it would work when designing a custom bore riding bullet mould. Am I missing something?
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Seems to me like it would work when designing a custom bore riding bullet mould. Am I missing something?
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No, not missing anything really, but slugging the bore and measuring the slug is bound to be more accurate. You didn't say what you're measuring, but you should measure both groove to groove and land to land, and if it's 5 groove rifling you'll have difficulty and will likely be measuring land to groove. Also, if it's an old military rifle, the bore is usually larger at the muzzle end from repeated cleanings and you'll get a larger than actual reading.
Would work, I'd just be real careful inserting a hardened piece of steel into a rifle bore.
Cat
Pin gauge is the best way.
Depending on action type a pin gage can be very accurate for measuring. one that is right at the muzzle should slide thru a clean bore to the action depending on bore. if it hangs up then a cleaning rod is needed to push it back out though. Most new bores are slightly larger at the breech than the muzzle unless there is wear in an older bore.
Snug fitting pin gage is a good way to check bore size but even Krieger bbls are crooked enough for a pin gage to hang up if you try to go all the thru.
Good point.
I guess it wouldn't take much "crook" to stop a 2 inch long pin gauge.
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Unless you have a specific jig it is the best way to slug odd numbered rifling.
To measure an odd-numbered bore (like a S&W, 5 lands/grooves) after driving it through the bore wrap your slug in something thin like aluminum foil, paper or some such. A .002 or 3 leaf from a feeler gauge works really well. Measure and subtract twice the thickness of the wrap.
Cat
if you do it right that method will give you the groove diameter.Quote:
Originally Posted by Catshooter
how do you get a bore measurement?
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