On Sat, 11 Mar 2023 12:24:46 -0800, Jeff Liebermann <
je...@cruzio.com>
wrote:
>On Sat, 11 Mar 2023 08:08:40 -0800 (PST), Tom Kunich
><
cycl...@gmail.com> wrote:
>
>>I should point out that "caliber" is the outside diameter of a bullet...
>
>Wrong. It's the inside diameter of the barrel:
><
https://en.wikipedia.org/wiki/Caliber>
>"In guns, particularly firearms, caliber is the specified nominal
>internal diameter of the gun barrel bore - regardless of how or where
>the bore is measured and whether the finished bore matches that
>specification."
>
>"The Complete List of Handgun Calibers"
><
http://www.ballistics101.com/handgun_calibers_list.php>
>Notice that the caliber (in the cartridge name column) is often (not
>always) different from the bullet diameter.
Well.... the "caliber" generally refers to the bore (inside diameter)
of the barrel while bullet diameter is (in modern ammunition) larger
then the bore diameter as the "rifling", which consists of grooves cut
into the "bore" of the barrel to induce spin, and therefore stability,
to the bullet in flight, mean that is the bullet was actual bore size
that the gas generated by the burning gun powder would leak past the
bullet, through the rifling grooves and (1) decrease the muzzle
velocity of the bullet and (2) rather quickly erode the bore.
And it also seem to be logical to name a cartridge by some common,
easily remembered, number. .32 caliber as opposed to a .299 caliber.
And quite often leaving off the decimal point as in 30-40 Krag, not a
.305-40 Krag.
Another point is "back in the good old days" they didn't have 1/1000th
inch. Back in my school days I worked (summer job) making bolts on a
lathe that had the cross feed calibrated in 128th of an inch.
Note here: I'm not that old and the lathe was in a shop that had been
owned by the same family since "God knows when" and in good old New
England practice, "why throw away something that still works" :-)
--
Cheers,
John B.