All info was found by DenKirson on xanga and is simply being passed along by me. [http://www.xanga.com/DenKirson]
Some diagrams were added to clear up confusion and explain with an image instead of a paragraph.
Damage and Range relation given an example image (that's the 1911).
Color-coding and a human shape to show the hit location multipliers.
Replaced Penetration text with imagery: "Power" in three levels, and "Thickness" of materials.
Hip Accuracy batched together, since most weapons in the same class have the same accuracy.
ALSO: Removed the AK47 discrepancy from the chart, putting it here.
Some weapons have differences in themselves with some attachments, or are different from all other weapons.
These differences may be intentional or erroneous, IW knows which is which.
-LMG Grips improve View Kick Center Speed (camera returning to where you were aiming) by a small but effective amount.
-M249 SAW with a Grip has improved Hip Accuracy (Between Assault and SMG hip accuracies).
-Both Shotgun Grips decrease overall View Kick.
-AK47's damage is 40-20 when equipped with a Silencer or Red Dot.
-M40A3 with an ACOG does 75 damage.
-AK-74u when equipped with a Silencer or Red Dot has the hip accuracy of the assault rifles.
-(CHANGED) P90 sprint time at "1.75" (all others have 1) - a patch for consoles has changed it to "1".
Stock Player health is 100.
Hardcore does two things:
-Health lowered to 30 (weapons are not changed in any way)
-No visible HUD
Weapon Images used in the Weapon Selection. Also, just because, the ammunition type and amounts.
Weapons of the same Ammo Type can share their ammo; carrying both, your Maximum Ammo increases to the sum of both maximums. ie MP5 + M9 pistol starts you off with 90 rounds and has a Max of 270.
Starting Ammunition is often three magazines (loaded mag included), and the Maximum is double the Starting, or six magazines worth (loaded Mag not included).
Bandolier gives you the Maximum plus a loaded magazine. ie a SAW has 300 + the loaded 100 belt.
Weapon Name ; Ammo Type ; Magazine Size ; Starting Ammo ; Max Ammo
ASSAULT

M16A1 ; 5.56×45 mm ; 30 ; 90 ; 180

AK-47 ; 7.62×39 mm ; 30 ; 90 ; 180

M4 Carbine ; 5.56×45 mm ; 30 ; 90 ; 180

G3 ; 7.62×51 mm ; 20 ; 60 ; 120

G36c ; 5.56×45 mm ; 30 ; 90 ; 180

M14 ; 7.62×51 mm ; 20 ; 60 ; 120

MP44 ; 7.92x33 mm ; 30 ; 90 ; 180
SUB MACHINE GUN

MP5 ; 9×19mm ; 30 ; 90 ; 180

Skorpion ; .32 ACP ; 20 ; 80 ; 160

Mini-Uzi ; 9×19mm ; 32 ; 96 ; 192

AK-74u ; 5.45×39 mm ; 30 ; 90 ; 180

P90 ; 5.7×28 mm ; 50 ; 150 ; 300
LIGHT MACHINE GUN

M249 SAW ; 5.56×45 mm (belt) ; 100 ; 200 ; 400

RPD ; 7.62×39 mm (belt) ; 100 ; 200 ; 300

M60E4 ; 7.62×51 mm (belt) ; 100 ; 200 ; 300
Note: LMG ammo can't be shared with other rifles of the same type.
SHOTGUN

Winchester 1200 ; 12 gague ; 7 ; 28 ; 56

Benelli M4 (M1014) ; 12 Gague ; 4 ; 20 ; 40
SNIPER RIFLE

M40A3 ; 7.62×51 mm ; 5 ; 20 ; 40

M21 ; 7.62×51 mm ; 10 ; 30 ; 60

Dragunov ; 7.62x54 mm R ; 10 ; 30 ; 60

R700 ; 7.62×51 mm ; 4 ; 16 ; 32

Barret .50 ; .50 BMG ; 10 ; 30 ; 60
PISTOL

Beretta M9 ; 9×19 mm ; 15 ; 45 ; 90

USP .45 ; .45 ACP ; 12 ; 36 ; 72

M1911A1 ; .45 ACP ; 8 ; 32 ; 64

Desert Eagle ; .50 AE ; 7 ; 21 ; 42
Notice the sniper ammo, some use the same ammo as the g3 and m14, so overkill can also be bandolier for those corresponding Sniper rifles! 2 perks for one!!!!!!!