What's the caliber of these guns?

[Ringo]

I’m a non-gunner who thought I had a handle on caliber as referring to the diameter of the round a guns uses in inches, i.e., a .50 caliber uses a .5 inch diameter round. Perhaps that’s wrong - if so, correct me, please.

I’m confused about a description of the main armament for the Battleship Texas (BB-35) that I read on an information pamphlet I got when visiting her. It described the main guns as 14" .50 caliber. A site I found on the Web gave the main guns as 14"/45 caliber.

Obviously, this use of “caliber” is at least a little bit different from that used with pistols and rifles. What does it mean?

[David_Simmons]

*Originally posted by Ringo *
**I’m a non-gunner who thought I had a handle on caliber as referring to the diameter of the round a guns uses in inches, i.e., a .50 caliber uses a .5 inch diameter round. Perhaps that’s wrong - if so, correct me, please.

I’m confused about a description of the main armament for the Battleship Texas (BB-35) that I read on an information pamphlet I got when visiting her. It described the main guns as 14" .50 caliber. A site I found on the Web gave the main guns as 14"/45 caliber.

Obviously, this use of “caliber” is at least a little bit different from that used with pistols and rifles. What does it mean? **

Caliber in small arms means the diameter of the bore. Caliber in big guns means the ratio of the length of the barrel to its diameter. For example a 6" gun called a 6"-50 caliber would have a barrel 25’ long. Your 14"/45 example would have a barrel a little over 38 ft. long.

I’m not sure but this might have originated to disinguish rifles which have long barrels from howitzers and mortars which have short barrels. The rifles being high caliber and the others being low.

[astro]

From Remington

The term “caliber” is used two ways in shooting sports. When referring to bullets and rifle barrels, caliber is defined as the diameter of a particular bullet, as well as the diameter of a rifle’s bore. Caliber is sometimes designated in US standard measurement (.30 caliber = 3-tenths of an inch in diameter) or in metric measurement (7mm caliber = 7 millimeters in diameter).

The second way caliber is used is when referring to cartridges and rifle chambers. In this instance, “caliber” designates a specific cartridge configuration that exactly matches the chamber of rifles with the same caliber. Although many of today’s popular deer hunting cartridges utilize .30-caliber bullets (including .30-30, .30-06, .308 and .300 Remington Ultra Mag) individual cartridge case designs and powder capacities result in dramatically different performance. Here, for instance, are three examples of rifle cartridges that use .30-caliber bullets with very different results.

A Dictionary of Units of Measurement

caliber (cal) [1]
a unit used to express the diameter of the bore of a gun. (The bore is the inside diameter of the gun barrel.) Traditionally, the diameter was stated in inches, so that “.22 caliber” referred to a pistol having a bore of 0.22 inches (5.588 mm). This usage is declining, because bore diameters of many guns are now stated directly in millimeters. “Caliber” is the American spelling; elsewhere the unit is spelled “calibre.”
caliber (cal) [2]

for naval guns, caliber is defined as the length of the gun barrel divided by the diameter of the bore. Thus a “50-caliber” gun on a warship has a barrel 50 times longer than its bore.

[Ringo]

OK, now it makes some sense. Thanks, guys.

[Bindlestiff]

I think the quote on caliber in naval guns is not exactly right. I learned as a US Navy Firecontrol Technician that a naval gun designated as a 3 inch 50 has an internal diameter of 3 inches and a length of 50 times that diameter or 150 inches.

In small arms, caliber started out meaning just the internal diameter of the barrel or the diameter of the ball/bullet. Later, especially with the development of modern powders it was used to designate more about the cartridge.

For instance there are at least two common 9mm calibers. One is called 9mm parabellum (parabellum is latin - for war- military) and the other is 9mm kurtz (short) aka .380. In .45 calibre there is the common .45 cartridge used in revolvers and the .45 acp used in semi-automatics. ACP stands for Automatic Colt Pistol. The shells are different size and shape. The ACP is notched at the rear and the rim is the same diameter as the case so it will work properly in the autoloader (semiautomatic).

So, in small arms caliber refers to the diameter, but also to various other characteristics on a more or less ad hoc basis.

[Joe_Cool]

*Originally posted by David Simmons *
Caliber in small arms means the diameter of the bore. Caliber in big guns means the ratio of the length of the barrel to its diameter. For example a 6" gun called a 6"-50 caliber would have a barrel 25’ long. Your 14"/45 example would have a barrel a little over 38 ft. long.

I got 52’6" for the 14"/45 gun.

14" x 45 = 630"
/12=52.5’

[David_Simmons]

*Originally posted by Joe_Cool *
**

I got 52’6" for the 14"/45 gun.

14" x 45 = 630"
/12=52.5’ **

You are absolutely correct. I didn’t save my work so I don’t know how I screwed it up. But I did.