why is it that 28, 20, 16, 12, 10, and whatnot are measured in Ga., but .410 is a caliber? something to do with the fact that it shares a bore with the .45, or what?
basically, what is the history behind that, if anyone knows?
Here's part of it.
The terms Bore and Guage date back to earliest muzzle loaders.
Early muskets and fowling pieces bore size was designated by how many round lead balls of bore size would go into a pound.
Bores of 2 were two balls to the pound, 32 Guage...32 balls to the pound.
The .410 bore diameter is much much later...
As is the no longer popular 9mm bore shotgun, whick saw limited success in the US but was popular in Europe....twas a rimfire. And cartridges available in Europe into the late 1980s.
Hence.....the majority of shotgun sizes date back to when ALL long guns were size designated by Guage or Bore.
And field and Naval pieces were sized by pounds. A four pounder fired a ball that weighed four pounds.
And the 9mm and .410 came along so much later and somehow got caliber designated like rifled arms.
If born much later.....12ga would likely be called .730 cal....or sumpin.
The 410 is an abomination that was developed by the Brits, although they will never admit to it. Probably got it's start as a BP rifle that someone (British of course) decided could do double duty as a fowling piece.
British ossifers could only take one gun with them when posted to India or some other colony, and had to find guns that would double as game guns and fowling pieces.
It would be 67.5 gauge if measured the usual way.
Why anyone would prefer the 410 over the magnificent 28 is beyond me. Ammo cost is similar and the 28 is so much more versatile and throws usefull patterns. The 410 is known as the "Idiot Stick" among skeet shooters.