Bullets: Why are there 2 different sizes? mm + caliber?

[JEDI]

and
http://www.convertunits.com/from/mm/to/caliber
How many mm in 1 caliber? The answer is 25.4.

so a 45caliber 1911 is actually .45? <mind blown>

so a 50mm dessert eagle is actually.. wait.. or is that 50cal?

see, so confusing.

why 2 metrics?
wished the gun manufacturers got together to had a standards consortium, like in computers. ie: usb port

 

[XavierMace]

so a 50mm dessert eagle is actually.. wait.. or is that 50cal?

If you thought about how big 50mm is, it wouldn't be confusing. It's inches vs millimeters, it's that simple.

 

[Eug]

There are 25.4 mm in one inch.

BTW, we have lots of different USB form factors. What's worse, the same form factor will provide completely different speeds.

 

[glenn1]

Caliber in standard units vs. metric. The .45ACP is a bit over 11mm (.451 to be super technically accurate). Likewise the 9mm is basically the same dimensions (.355) as the .357 Magnum and .38 special rounds.

 

[Charmonium]

It gets worse. You have some calibers like 7.62mm that just seem weird. I mean, who really cares about a few hundredths of a millimeter.

edit: never mind. 7.62 = 30 cal

 

[MongGrel]

Even some things in the same caliber vary, of course.

You can use .38 special caliber in a .357 Magnum just to practice with as the ammo is cheaper. Used to be, not sure if still true price wise.

http://www.diffen.com/difference/.357_Magnum_vs_.38_Special

And some ammo just varies in the same range. You wouldn't be shooting .22 magnum out of a standard .22

Lots of variables.

 

[glenn1]

It gets worse. You have some calibers like 7.62mm that just seem weird. I mean, who really cares about a few hundredths of a millimeter.

edit: never mind. 7.62 = 30 cal

Cartridge length and bullet size come into play as well as diameter. For example in the ~7.62mm format you have dozens of unique loadings from 7.62x39, 7.62x55, 7.62x51 (aka .308 Winchester), .30 Carbine, and tons of others.

 

[cbrunny]

Another great example of metric trumping whatever a caliber is. Purely undisputable.

 

[MongGrel]

Another great example of metric trumping whatever a caliber is. Purely undisputable.

If you say so.

 

[EliteRetard]

https://www.youtube.com/watch?v=QfDoQwIAaXg

Here's this again, just for fun.

 

[Ronstang]

Add in the use of caliber as a measurement of length for artillery and it gets even more interesting until you understand

 

[LTC8K6]

For 9mm you have 9X17, 9X18, 9X19 traditionally known in order as .380 or 9mm short/kurz, 9mm Makarov, and 9mm parabellum/Luger/just plain 9mm.

And those are just the most common "9mm" calibers.

https://en.wikipedia.org/wiki/9_mm_caliber

.45ACP = .452" = 11.43×23 mm

.44 Magnum is actually .429"

.38 Special is actually .357"

 

[Jaepheth]

My Colt Navy is .44 caliber and shoots .454" diameter ball while my .44 caliber Pennsylvania Flintlock shoots .433 ball...

I had wanted to only have 1 ammo type when I got the rifle, but had a brain fart and completely neglected that the rifle shoots patched ammunition while the revolver does not :/

 

[slag]

https://www.youtube.com/watch?feature=player_detailpage&v=6Pkq_eBHXJ4#t=61

 

[edro]

'merica! ...that's why!

 

[clamum]

I don't find it that difficult really, but I've been reading about gun "stuff" and shooting for years. The thing that surprised me the most, when I was first getting into firearms stuff, was the whole 9mm Luger ~ .357 Magnum ~ .38 Special (as far as caliber diameter goes).

 

[LTC8K6]

9mm Luger = .355" I think.

 

[Blackjack200]

Another great example of metric trumping whatever a caliber is. Purely undisputable.

8" gun > 155mm

16" gun > all

https://en.wikipedia.org/wiki/16"/50_caliber_Mark_7_gun

 

[TwiceOver]

Thanks for the info everyone. I always wondered what the difference was.

See, gun threads can be informative instead of a shit on everyone fest.

 

[JEDI]

Caliber in standard units vs. metric. The .45ACP is a bit over 11mm (.451 to be super technically accurate). Likewise the 9mm is basically the same dimensions (.355) as the .357 Magnum and .38 special rounds.

wait.. so I can put a 9mm into my 357 magnum revolver??
(9mm is cheaper than 38 specals!)

 

[JulesMaximus]

and
http://www.convertunits.com/from/mm/to/caliber
How many mm in 1 caliber? The answer is 25.4.

so a 45caliber 1911 is actually .45? <mind blown>

so a 50mm dessert eagle is actually.. wait.. or is that 50cal?

see, so confusing.

why 2 metrics?
wished the gun manufacturers got together to had a standards consortium, like in computers. ie: usb port

Because:

Murica (standard)
Rest of the world (metric system)

 

[JulesMaximus]

wait.. so I can put a 9mm into my 357 magnum revolver??
(9mm is cheaper than 38 specals!)

No, you cannot. A 9mm case is much shorter than .357 or .38 special.

Also, .357 and .38 cases have a lip that keeps the shell from falling too far into the cylinder. 9mm cases don't have that and would fall too far into the cylinder to fire.

Moon clips might work but you would foul the cylinder which would require more frequent cleaning for sure if you wanted to load .357 or .38 special in the gun again. Most people just shoot .38 special in their .357 Magnum because it is cheaper. Not sure if 9mm is much cheaper than .38 special.