Real calibers

Here's a list of some of calibers found in modelguns.
I compiled it for my own reference, it would be a waste not to post it :-)

.50 AE (12.7mm) - used by Desert Eagle pistol.
.45 ACP (11.43mm) - designed by Browning, used in Colt 1911, Thompson M1928/1921.
.44-40 Winchester (11.2mm) - used in Winchester rifles.
.40 S&W (10.2mm) - used in Beretta M96.
.380 ACP (9mm Browning/Short/Kurz, 9x17mm) - designed by Browning, used in Beretta M84.
.38 Special (9x29mmR) - rimmed revolver cartridge, used mostly in Smith&Wesson firearms.
.357 Magnum - rimmed revolver cartridge, used in Smith&Wesson firearms.
9mm Luger (9mm Parabellum, 9x19mm) - most popular pistol cartridge used in most modern firearms.
8mm Nanbu (8x22mm) - Japanese cartridge, used in Nanbu Type 14 pistol.
7.92mm Mauser (7.92x57mm, 8mm Mauser) - used in Mauser 98k.
7.92mm Kurz (7.92x33mm) - used in MP44
.32 ACP (7.65mm Browning, 7.65x17mm) - designed by Browning, used in pistols: Browning 1910, Colt .32.
7.63 Mauser (7.63x25mm) - used in Mauser C96.
7mm Nanbu (7x20mm) - Japanese pistol cartridge, used in Baby Nanbu pistol.
.25 ACP (6.35mm) - small caliber pistol cartridge designed by Browning, used in Walther PPK, Colt .25.
.223 Remington (5.56mm NATO, 5.56x45mm) - standardized rifle cartridge, used in M16/M4/CAR15 series automatic rifles.
.22 LR (5.6mm, 5.6x15mmR) - small caliber cartridge used for sports shooting: Colt Woodsman, Walther GSP.