Human Weapons
Pistol: 12 shots per clip
Headshot kill: 3 shots
Effectiveness: overall good weapon, snipers use it, and so do flag runners.
Assault Rifle:60 shots per clip
Headshot kill: No idea
Effectiveness: Close range (little longer than shotgun) long range very inaccurate.
Shotgun: 8 rounds (reload by shell count)
Headshot kill: 1 shot, must be close
Effectiveness: Used at a close range, deadly, used as a sniper, you just wasted a shell.
Sniper Rifle: 4 shots per clip
Headshot kill: 1 shot
Effectiveness: Unzoomed sniper easier than Counter-Strike, long range weapon.
Fragmentation Grenade: max 4 grenades per type of grenade
Headshot kill: not a headshot weapon
Effectiveness: Not a single shot kill, but if you hit someone with it shoot at them with whatever you got.
Rocket Launcher: 2 rounds fully loaded
Headshot: headshot doesn't matter, fire this within a close enough proximity of them they die.
Effectiveness: not suggested for close range (might kill yourself), long range slow shot, easy to dodge.
Covenant Weapons
Plasma Pistol: 100 energy units
Headshot: Charge up: 1, burst fire: unknown
Effectiveness: A charge up shot with a few bursts of fire is effective at medium range. The charge up also seeks the player slightly.
Plasma Rifle: 100 energy units
Headshot kill: Unknown
Effectiveness: ranged, a little harder, but overall good weapon.
Needler: 20 round clip type thing
Headshot kill: not used on head
Effectiveness: get twenty of the little needles in them, they explode in a painful pink explosion. The needles seek pretty well.
Plasma Grenade: max 4 grenades per type of grenade
Headshot: if you manage to stick one to someone's head, good job, otherwise it sticks.
Effectiveness: if it sticks your target, he's dead end of that life.
Vehicles
Warthog (Human): 3 person assault jeep
Weapons: passenger can fire his weapons that he uses on the ground. One rather large gun in the back provides a suppressing fire.
Usual Purpose: This vehicle with medium fire power and good speed makes an excellent flag run vehicle, and can be moved anywhere.
Scorpion Tank (Human): 1 driver/gunner, 4 passenger
Weapons: 4 passengers can fire ground weapons, driver can fire large cannon, and chain gun.
Usual Purpose: This can back-up the warthog in a flag run. In Blood Gulch, it can be used as an artillery and destroy any attackers. It is very slow though.
Ghost (Covenant): 1 driver/gunner
Weapons: Freeze gun that restricts movement of the person or thing being shot.
Usual Purpose: Annoying the heck outta anyone. This is very maneuverable and can get in a base but it is harder to get out.
Banshee (Covenant) (Campaign only): 1 pilot/gunner
Weapons: 2 freeze guns (like ghost), 1 Fuel rod cannon
Usual Purpose: Used in some missions to get around the high canyons rather than making you walk all over the place.
Wraith (Covenant Tank) (Campaign only) (Non-pilotable): 1 pilot/gunner
Weapons: Artillery like cannon
Usual Purpose: annoy the hell out of you during the campaign.
