7.62 mm (or 30 caliber) and 5.56 mm (or 223 caliber) are common rifle cartridges.
Pistols, machine guns, and artillery will of course be different from these.
Countries that are members of the UN use guns.
you can not use metal bbs in airsoft guns at all. they are not compatible because they are both built differently.
No such thing. You can have small caliber but not low caliber.
With VERY FEW exceptions all BB guns use the same size BB .177 Caliber.
7.65mm is .32 caliber. I own one of these guns and love it.
4.5 cal (9mm) like most guns
any single or double action semi-automatic pistol listed as a 40 caliber pistol...............
Some guns yes, but most guns would require gunsmithing to change caliber.
No. most guns are .68 caliber, however there are some .50 and .43 caliber markers and pistols.
Pellet guns tend to come in two standard caliber sizes. The first smaller caliber is the most common for pellets guns and is .177 caliber. The second is .22 caliber that can be found on some higher powered pellet gun models.
The caliber
.68. Almost all guns are this caliber.