The size is indicated by the number before the firearm, i.e., 2 mm caliber, 3 mm caliber and so on. The higher the caliber, the larger the bullet. Remember that as gun sizes evolve, so do the bullets.
Bullet Size: Handguns and Pistols
For the Swiss Mini Gun, the 2.34mm was employed. Other small bullets are the 3mm Kolibri and the 4.25mm Liliput. Among the well known .22 cartridges are the .22 BB, the 22 CB, the .22 Short, the .22 Long Rifle and the .22 WMR (.22 Magnum). The Winchester Magnum had a cartridge measuring .256. The Tokarev’s measures 7.62x25mm.
The measurements of other handgun bullets are as follows: 8x22mm for the Nambu, the 38 Short Colt, the .38 Long Colt .38 Caliber and the 380 Revolver. The latter two, along with the .38 Special, are among the most well known in the world. Other well known bullets and guns are the 357 Super Magnum, the 9x19mm Parabellum .38-40 Winchester and the .40 Smith & Wesson.
Bullet Size: Rifles (Centerfire)
The measurements given here are in inches.
Among the well known are the .17 Remington, the .22 BR Remington, the .218 Bee, the .22 Hornet and the .221 Fireball. Other Remington cartridges were the .44 Remington Magnum, and the .35 Remington. The Winchester also came out with several cartridges.
Among them are the .25-20 Winchester, the .284 Winchester and the 405 Winchester. Other centerfire cartridges are the .50 Beowulf, the .45-70 Government, the .50 Browning machine gun, the .416 Weatherby Magnum and the 224 Weatherby Magnum.
Bullet Size: Large Caliber
This includes the 50-70 Government, the .50-110 Winchester, the .50-140 Sharps and the .50 Beowulf. The .500 Black Powder Express, the .500/450 Nitro Express and the 510 DTC Europ also belong to the .50 caliber.
Also belonging to this are the .577 Tyrannosaur, the 577 Snider and the 577/450 Martini-Henry. Also included in this list are the 600 Nitro Express, the 950 JDJ, the 700 AHR and the .700 Nitro Express.
Some rim fire cartridges are the .17 Hornady Mach 2 (.17HM2), the 5mm Remington Mag, the .22 WMR (.22 Magnum), the .22 WRF, the .22 Long and the .22 Long Rifle.
Bullet Size: Older Types
Some of these are quite obscure but are prized by gun collectors. They include the .14 Walker Hornet, the 17 Ackley Bee, 17 PMC/Aguila, 17/23 SMC .19 Calhoon Hornet and the .19 Badger.
The .20 Tactical, the .219 Donaldson Wasp, the .22 Cheetah and the .22-243 Middlestead are other old types.
Also included in the list of obscure types are the .275 H&H Magnum, the .300 ICL Grizzly, the 300 Lapua Magnum, the .338 Whisper (Series 1) and the .40-65 Winchester.
The .425 Westley Richards, the .45-110 Sharps, the .450 Watts Magnum, .470 Capstick, .475 OKH, .475 Ackley and .500 Phantom are almost always included in lists of proprietary and obscure firearms and cartridges.
Although bullet sizes are measured in millimeters, they also have equivalent in inches. Larger firearms like machine guns use bigger ammunition.