100-1000 USD
The highest caliber machine gun in standard use is the .50 Cal. Gatling guns are used in 20mm caliber. XXXXXXXXX Russia and China use a heavy machine gun larger than the .50 cal BMG- it is the Vladmirov KDV (for the Russians), in caliber 14.5mm x 115.
No such thing. You can have small caliber but not low caliber.
the are also chambered for the 38 caliber, 9mm caliber and 22 caliber
What caliber of man are you looking for? What caliber of gun are you looking for?
.32 caliber
30 caliber
.45 caliber
It's more a matter of where it's manufactured and by whom than the caliber. Several non-NATO nations also manufacture NATO standard ammo. For example, Russia manufactures the 5.56x45 and 7.62x51 to go along with export versions of NATO caliber firearms they manufacture, such as the AK-101. Their steel cased rounds are much less expensive than, say, American made M855 ammo.
A 5.56mm is the same thing as a .225 caliber. If you do the math, a 30 caliber is MUCH bigger!
a .22 caliber
.32 caliber