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backcast
04-15-2018, 03:17 PM
I'm a rookie... Could someone please explain what the numbers mean for cal.'s like 22-250 or 38-40 etc. etc.

Thanks...

Robinhood
04-15-2018, 03:53 PM
The numbers can have different meanings. 22-250 is a 22 caliber bullet in a 250 savage case. A 30-06 is a 30 caliber in a case designed in 1906. Or something like that. 25-06, 6.5-06 yada yada. Some are caliber x weight of black powder, like 45-70. The 7mm08 is a 308 necked down to 7mm.

thatguyshm
04-21-2018, 01:25 PM
http://www.firearmsid.com/a_bulletidcal.htm

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243LPR
04-21-2018, 01:51 PM
Pretty sure the 38-40 is actually a 40 cal bullet with the original load of 40 gs of black powder. Can be confusing. Like why do they call it a 38 special when it's a .357 bullet?

GaryB
04-21-2018, 04:56 PM
Pretty sure the 38-40 is actually a 40 cal bullet with the original load of 40 gs of black powder. Can be confusing. Like why do they call it a 38 special when it's a .357 bullet?

and the 38 special came before the 357 mag. Now there is a 357 Sig which is actually a 9mm(.355). Yikes!

eddiesindian
04-21-2018, 06:53 PM
Yep...goes on and on...remington 260 caliber is really a .264 diameter or 6.5 08

Stumpkiller
04-21-2018, 09:57 PM
Some cartridges are described with land measurements, some are groove diameters. Some are neither but just because a space was available on the ballistic tables; i.e..225 Winchester, .223 Remington, .270 Winchester, .33 Nosler.

Why do they name cars the way they do? Same concept. It's more marketing than engineering.