Author Topic: Caliber Confusion (Read 840 times)

Toasty · « **on:** June 03, 2003, 05:34:53 PM »

Call me a newb, but I do not know what a gun's caliber refers to and what its importance is. Needless to say, it obviously is important otherwise I wouldn't be hearing the term so much. Can someone help me out here? Thanks for your time.

Hud · « **Reply #1 on:** June 03, 2003, 06:00:15 PM »

A caliber is one onehundreth of an inch. 25 caliber is a 1/4 inch and 50 caliber is 1/2 inch. As far as the names go there is no one system that applies to all of them.

Here are some explainations of cartridge names.

45-70, 45 caliber and 70 grains of blackpowder
44-40, 44 caliber and 40 grains of blackpowder
38-40, 40 caliber and 38 grains of blackpowder
30-30, 30 caliber (308) and 30 grains of smokeless powder.
30-06, 30 caliber (308) and improved in 1906 (introduced in 1903)
308 Win, 30 caliber and the same case family as the 30-06, but shorter.
243 Win, 308 case necked down to .243.
358 Win, 308 case necked up to .358.
7mm/08, 308 case necked down to .284
35 Whelen, 30-06 necked up to 358 caliber and named after Whelen.
270 Win., 30-06 necked down to .277.

250/3000 or 250 Savage, Same case family as the 308 & 30-06 but shorter yet than the 308 and is in 257 caliber. The 3000 means it will push a bullet (87grain) to 3000 FPS which was a big deal when it was introduced.

22/250, It is the 250/3000 necked down to .224

Then there is all the metric ones, all the magnums both belted and beltless, and all the wildcats.
Hope this helps.

Hud

HoCoMDHunter · « **Reply #2 on:** June 04, 2003, 05:24:32 AM »

For a beginner, many of the caliber designations will make little sense. After you get into it things will start to make sense. Here's one that confused me when I was considering my first firearm---
The difference between 38 special and 357 magnum. You wouldn't guess it from their names but both of these have the same diameter bullet (.357 inches). The 38 is a less powerful and shorter cartridge than the 357. If your gun is a 38 special you can shoot only 38 special ammo in it. You can shoot both 38s and 357s in a 357 revolver. Hope this helps.

myronman3 · « **Reply #3 on:** June 04, 2003, 03:20:19 PM »

for a beginner it can be very confusing. always ask rom someone who is knowlegable and reliable BEFORE you try something. this is a great place to learn.

Mikey · « **Reply #4 on:** June 05, 2003, 04:29:14 AM »

Toasty: what you need is a Lyman Reloading Manual to help you resolve all this confusion. Find an older one. For each caliber Lyman introduces the subject with a bit of history on the orgins of the caliber and its general uses, positives and negatives. You have already received a host of excellent and very accurate inforamtion but I would still suggest one of the loading manuals for reference. I suggest the Lyman Manual for its informative basis as well as the diagrams and measurements it provides.

If that doesn't work for you , or if you have some specific questions about some specific calibers, ask the Graybeard. He's older than the hills and knows more about boolets and calibers and everything than anyone else. He is an incredible resource, a wealth of information and a great one to learn from. Hope this helps. Mikey.

securitysix · « **Reply #5 on:** June 05, 2003, 04:41:45 AM »

I will second the recommendation to get a good manual. Lyman prints a great manual, but any of the major reloading manuals should help. Speer #13 has good information in it. Until you get around to that, try these links:

For pistol cartridge info
For rifle cartridge info
For wildcat cartridge info

They're not perfect, but they are a good start.

BigMike · « **Reply #6 on:** June 18, 2003, 03:35:54 PM »

There is one more "Caliber" to discuss.

Caliber is properly the ratio of barrel length to bore diameter.
Although this definition is not used much outside of artillery.
Example: a half inch bore, 36 inch barrel is 72 "caliber"

Just in case you wondered about shotguns, "gauge" is a whole
separate story. Shotgun gauge refers to the number of lead spheres
of the bore diameter that would make up a pound.
An example will help. A 12 gauge shotgun would have the bore
diameter of 1/12 of a pound of lead. ==> 1.333 ounce

Lead has a density of 6.557 ounces per cubic inch (11.3437 grams/cc)
So we need a ball of lead that is 1.333/6.557 cubic inches in volume.
Using the formula for volume of a sphere = 4/3 Pi Rcubed and solving
for the radius in inches we get 0.3647 inch which when multiplied by 2
to make it a diameter is 0.7294 which when rounded is the accepted bore
of 0.729 inch for a 12 gauge shotgun.

Cheers!

BigMike