I know I saw a post somewhere on measuring groove diameter in barrels with an odd number of grooves (like S&Ws).
Could someone kindly point to it?
I know I saw a post somewhere on measuring groove diameter in barrels with an odd number of grooves (like S&Ws).
Could someone kindly point to it?
http://castboolits.gunloads.com/goog...57j16494987j25
The link is to a search result that gives links to several threads on the topic.
In lieu of a mathematical value to assign to a slug, try this simple test. Push a soft lead ball through the bore, then see if it will go into the cylinder throats from the front. If it does, then the throat to bore relationship is likely correct.
It doesn't really tell you any decimal figures, it tells you that the throats are larger than groove diameter, and if you size the boolit to fit the throat, the boolit will be of sufficient diameter to seal in the bore and likely shoot well.
This is the poor man's cylinder mic if you will..
Got a .22 .30 .32 .357 .38 .40 .41 .44 .45 .480 or .500 S&W cylinder that needs throats honed? 9mm, 10mm/40S&W, 45 ACP pistol barrel that won't "plunk" your handloads? 480 Ruger or 475 Linebaugh cylinder that needs the "step" reamed to 6° 30min chamfer? Click here to send me a PM You can also find me on Facebook Click Here.
Have access to a 3d printer?
If so, I created a model for a 108° (5 groove) v-block adapters for both a micrometer and calipers that you can print.
http://castboolits.gunloads.com/show...ove-slug/page2
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