View Full Version : Calibers and mm?

11-13-2005, 11:50 PM
I one of the guys who don't know jack about guns and I'm wondering what caliber and mm refer to when talking about armement? 'Coz ".50 cals pwnz 12mm MG!" equals "My finely engraved katana roxorz your leather-griped machete" to me. Charts would be cool too http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

11-14-2005, 12:18 AM

11-14-2005, 12:20 AM
Calibre - calibrate - calibration.

From the Arabic - quâlib - a mould (for bullets).

To remove from such a mould Exquâlib . Hence - Excaliber.

Sorry no chart http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

11-14-2005, 12:31 AM
Look here:

11-14-2005, 12:38 AM
Originally posted by Kuna15:

http://forums.ubi.com/images/smilies/25.gif I like

11-14-2005, 01:06 AM
Literally tons of various info+pictures about guns and ammunition.


11-14-2005, 01:29 AM
nice. i wonder if they include star shells in there aswell.

11-14-2005, 01:54 AM
Basically, calibre refers to the diameter of the bullet (or grenade) when seen from the front or back. Calibre can be given in inches (the .50 means the bullet is a half inch diameter), metric millimetres (the 12mm) or in an antiquated system of €œbullets to the pound€, not applicable to aircraft guns.

.50 calibre, or a half inch, is 12,7 millimetre, making the 12mm HMG and the .50 HMG roughly equal. However, as you can see from the photo Kunha posted, bullet/grenade size is not everything. For non-explosive projectiles, speed is an equally important factor. The speed is mainly a result of the amount of gunpowder in the cartridge case. Again, referring to Kunhas picture, the Mk. 108 has a big, bad projectile, but the projectile is almost as large as the cartridge case. This means the round is slow, and would be no more effective than a big pistol round, had it not been for it€s considerable content of explosives.

The .50 (in the right corner) is a nicely balanced round, easily comparable to the rifle round in the left corner. It has very good ballistic properties, but is still only an oversized rifle round.

11-14-2005, 02:26 AM
lenght gun barrel effect speed round go easy see type-99-I 20mm and type-99-II 20mm far more power longer gun

11-14-2005, 02:48 AM
Nakamura_kenji is right off coerce, the gun it self has a very big influence on the rounds performance. Generally, the longer the barrels the faster and more precise will the projectile be. Also, a heavy gun will give a sturdier platform from which to fire.

The problem with aircraft guns is that long barrels and heavy mechanisms are things than you don't want on a plane. It will weigh the plane down, and long barrels will poke out from the wings (like the very effective Hispano barrels poke out of the wings of a Spitfire). Aircraft guns are often very much a compromise between gun efficiency on one side and aircraft efficiency on the other. Basically, an aircraft gun is less reliable, less accurate and has lower bullet speed than a land based gun fire ring the same round.

11-14-2005, 04:34 AM
Barrel length is typically determined by the amount/duration of meaningful barrel pressure. A small charge usually determines a short barrel and doubling the barrel length of an ideally configured weapon will likely reduce muzzle velocity. Longer barrels usually indicate larger charges. To compound the caliber nomenclature a bit, barrel length can be given in calibers as well, as in a ratio of that barrel's bore versus length.

I'm an expert . . . don't you dare question me! http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif Seriously . . . (not really)

11-14-2005, 04:48 AM
yes you right to long barrel cause much more drag/friction than benefit get. though friendly say aircraft cannon often gun were much short than what best speed/acuracy a6m type-99-I had short barrel so gun no stick out from wing give horrible ballestic/acuracy but better aredynamic.

other good example be orignal rhinemetal 120mm and the rhinemetal 120mm L44 which much great length

11-14-2005, 06:17 AM
Originally posted by Waldo.Pepper:
Calibre - calibrate - calibration.

From the Arabic - quâlib - a mould (for bullets).

To remove from such a mould Exquâlib . Hence - Excaliber.

Sorry no chart http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif Hang on, so where does that watery tart fit in?