A Beretta 92FS is used by Big Daddy (Nicolas Cage) in an early scene to shoot his daughter Hitgirl (Chloe Moretz) to show what is like to be shot with a bullet proof vest on, and later when he attacks a group of mobsters at Frank's Lumber warehouse.
A Heckler & Koch P7 pistol is seen on the wall in Damon Macready's armory room.
Heckler & Koch USP
One of D'Amico's men is armed with a Heckler & Koch USP (of unknown caliber, probably .45 ACP) during the final shootout at D'Amico's home.
Heckler & Koch USP Compact
A Heckler & Koch USP Compact is wielded "akimbo"-style by Mindy Macready aka "Hit Girl" (Chloe Moretz) along side a SIG Sauer P232 (left hand). A two toned H&K USP Compact is wielded by a thug. She also uses one in the POV scene and during the rescue, with a rail mounted flashlight in tactical strobe mode.
Jericho 941
A Jericho 941 pistol is seen on the wall in Damon Macready's armory room.
SIG-Sauer P220
One of the mobsters guarding Frank D'Amico's apartment is armed with a SIG-Sauer P220.
SIG-Sauer P226
One of Frank D'Amico's men is armed with a SIG-Sauer P226.
SIG-Sauer P232
Hit Girl uses a SIG-Sauer P232 during the shootout at D'Amico's home. Hit Girl reloads the P232 by dumping the magazine with only one hand, which is impossible because the magazine release is located at the heel of the grip.
Desert Eagle Mark I
Shotguns
Mossberg 500
Damon Macready aka "Big Daddy" seizes a Mossberg 500 shotgun with an extended magazine tube from one of Frank D'Amico's men and uses it during the gunbattle at Frank's Lumber warehouse.
Armsel Protecta
A heavily modified Armsel Protecta is used by one of the mobsters shooting at Hit Girl during the finale. It differs from most examples of the weapon due to having a muzzle brake, a M1913 rail over the drum and the back half of the weapon modified to take a M4 style stock.
Franchi SPAS-12
Two Franchi SPAS-12 (one with stock folded and one with stock removed) can be seen on the wall of Damon Macready's office.
Sub-machine Guns
Heckler & Koch MP5K
A Heckler & Koch MP5K is fired by one of Frank D'Amico's men at Hit Girl during the execution rescue scene. Hit girl is also seen loading and pointing one, with a 15 round magazine, at Kick-Ass in the Mcready's armory before placing it in her tote-bag prior to the assault on the D'Amico's penthouse (it's never seen again).
Two L85A1 with SUSAT scope are seen in the Macready's arsenal.
M4A1 Carbine
Several M4A1 carbines with scopes and foregrips are seen in the Macready's armory.
SIG SG552
SIG SG 552 rifles with top-rails, scopes, silencers and B&T Quad Rail handguards are seen among the weapons in the Macready's armory. Later, a mobster wildly fires a SG 552 at Hit Girl when she attacks Frank D'Amico's apartment.
Steyr AUG
A Steyr AUG is also among the many weapons seen in the Macready's arsenal.
Unknown Sniper Rifle
Damon Macready aka "Big Daddy" uses a suppressed sniper rifle of unknown make to cover Hit Girl during the fight at Rasul's (Kofi Natei) apartment.
An M14 with a folded bipod can be seen on Macready's wall.
Heavy Weapon
GE M134 Minigun
Dave Lizewski aka "Kick Ass" uses two gatling guns similar to GE M134 miniguns mounted on a jetpack during the finale. These are obviously custom built as they are too small to be the real thing or a 1/1 scale replica thereof, also they have no drive motors just the rotor body and feeder/delinker.
Mk 153 Mod 0 SMAW
A Mk 153 Mod 0 SMAW, referred to throughout the movie as a "bazooka", is used by Huge Goon (Stu Riley) during the finale. The trigger/firing mechanism looks very odd on the Mk 153 used in the movie. It looked like it had the frame of a H&K MK23 pistol mated to the lower receiver of a H&K MP5 sub-machine gun.
M249 Machine Gun
Two M249 machine guns can be seen in Macready's armory.
M67 Hand Grenade
M67 hand grenades are seen attached to Damon Macready's aka "Big Daddy" uniform.
Other guns in the armory
During Sergeant Marcus Williams' visit to the safehouse various guns can be seen, among them:
a couple of G36C with Aimpoint dots,
a G36E equipped with an AG36 grenade launcher,
a M14 with a bipod,
a scoped Remington M700,
a Psg-1 (rumored to be the one used by Big-Daddy to kill Rasul's doorguard),
3 M16, one of them equipped with a m203 grenade launcher,
a couple of mini uzi,
and an HK SL8