The M249 is typically fed from a belt... 100 round "nutsacks" and 200 round plastic drums are often used. It can also be magazine fed from STANAG 4179 magazines (the type used in the M16 and several other rifles). Those can be whatever capacity they're manufactured for, but 30 rounds is typical.
600 to 800 rounds
The basic load for a M249 Squad Automatic Weapon (SAW) in the Army is typically 600 rounds of 5.56mm ammunition. This load is divided into two 200-round drums and one 100-round belt. It is important for soldiers to carry enough ammunition to sustain firepower during combat operations, while also considering the weight and mobility constraints.
They don't carry ammo in boxes. Basic load depends on the weapon system. 210 rounds for the M4 or M16, 600 - 800 rounds for the M249, 800 - 1000 rounds for the M240.
Depends on what type of machine gun. For most Western/NATO machine guns, the belts come packaged in 100 rounds on M13 disintegrating steel links, and these can be linked together to form as long a belt as one wishes. The linked ammunition for the FN Minimi/M249 SAW typically comes in 100 or 200 round linked increments. For your heavy 12.7mm/.50 machine guns, it's usually 100 rounds linked per box of ammo.
it depends what gun it is but usually there is 8 bullets in a semi-automatic pistol. with some there are only 7 bullets in the magazine but to achieve the maximum rounds the gun can carry the 7 shot mag is inserted, the pistol is cocked and the mag is removed, another bullet is inserted and the mag is again placed inside the gun.
The M249 Squad Automatic Weapon fires the same 5.56x45mm cartridge used by the M16 and M4.
The maximum effective range of the M249 light machine gun is 1,000 yards (910 meters).
This generally refers to the 8mm Hotchkiss M-1915 which switched the weapon from a 30 round strip of ammunition to a 249 cartridge belt. Unless you are talking about the US M249 machine gun in 5.56mm NATO. M249 was originally designed and produced by the Belgian firm FN Herstal as the MINIMI (French acronym for MINI MItralleuse)
FN Herstal
CLP
The M249 light machine gun has a maximum effective range of about 800 meters for an area target.