if i pick a light body type then that means that i can only use light weapons but if i pick a medium body type dose that mean that i can use medium weapons or both medium and light weapns?

Think it's like this:

Heavy:

Primary: Heavy Weapon (ex: Heavy Shotgun, Heavy Minigun, Heavy Grenade Launcher)
Secondary: Assault Rifle

Medium:

Primary: Assault Rifle
Secondary: Shotgun, Handgun

Light:

Primary: SMG
Secondary: Handgun, Light Rifle (Sniper Rifle)

If I made any mistakes in this list, please do correct - Anyways, this should give you a hint atleast

light can use smg, pistol and short rifles
medium can use the above + assault rifles, grenade launcher and shotgun
heavy can use all the above + lmg, automatic shotty and automatic grenade launcher

Alright, so this is how it looks:

Heavy:
Primary-miniguns, automatic grenade launchers, automatic shotguns
Secondary- Assault rifles, pump/semi shotguns

Medium:
Primary - Assault rifles, pump/semi shotguns
Secondary - SMG, short rifles

Light:
Primary - SMG, short rifles
Secondary - pistols, revolvers, machine pistols

Zombie is the closest. Nikto has the right idea, but I'm not sure if his description would make sense if you didn't know the system beforehand.

Only things id like to change are that based on the real world weapons that the shotguns are based on, I think that the Medium shotgun is a pump action with a 4 shot tube (civilian xm1014) or an 8 shot tube (Military xm1014) and the Heavy shotgun is a semi auto with 8, 12, or 16 shots (depends on the length of the magazine).

Heavies also have the choice of using heavy machine guns in addition to the minigun. Interestingly, the one machine gun that we have identified, the M249, is an LMG but one of the high res wallpaper pics shows it in detail, and it clearly has HMG written on the side.

There is also the ability for players to choose a weaker weapon, a heavy could use a short rifle if they wanted to.

They can but why would they when you can carry a big gun :celebration:

Handicap vs a worse team? I know I'm not the only one who does such things.

heavy with a handgun whooping mediums with an assault rifle

Why stop at one when you could be a heavy with a revolver and a machine pistol.

well i'll be playing with clanbuddies most of the time, so i want to have one usefull gun on me at all times.
and either way, you might run into that one good guy on their team

It's been stated multiple times in the past on how the weapon system will work:
Heavy: Primary heavy weapon (minigun, heavy sg etc), secondary medium (AR/shotty etc) or light (SMG/light rifle)
Medium: Primary medium, secondary light
Light: Primary light, secondary handgun.

A heavy can run 2 smgs or 2 ars if he wanted to, those are just the limitations.