Hellboy's (Ron Perlman) personal sidearm, the Samaritan, of which he acquired in the '50s, he named it the "Samaritan" because it puts monsters out of their misery. The metal of the gun is forged from a combination of Irish church bells, cold iron from crucifixes, blessed silver, and other mystic metals. The grips have the BPRD insignia on each side and the wood of the grips is believed to be that of the cross of which Jesus Christ was crucified on. The gun has immense muzzle energy and is believed capable of breaking a normal mans arm due to great recoil. The gun holds 4 shots (although in the film he fires 8) and fires bullets HB makes himself as a hobby. He puts Holy water, Garlic cloves, and white oak shavings in his special rounds. As he calls them, "The Works." The gun uses a tip-open action similar to a Webley or Schofield action revolver. It fires double action and single action. When out of bullets, HB likes to use it as a hammer as this cannon weighs around 10 pounds!
Handguns
Luger P08
Karl Ruprecht Kroenen (Ladislav Beran) uses a Luger P08 early in the film and after firing eight shots, he tosses it down to use his blades.
Heckler & Koch USP Compact
Both John Meyers (Rupert Evans) and Clay (Corey Johnson) use Heckler & Koch USP Compact (modified with regular USP hammers) as their personal sidearms throughout the film.
Note: Meyers gun is a fake, as when firing the action does not function and no shells fly out. Guards at the museum are seen using both stainless steel slide version and regular versions as well.
Clay's gun is a blank gun as seen when he confronts Kroenen.
Colt M1911A1
In the opening sequence, Sgt. Whitman (Angus MacInnes) first offers his M1911A1 to Young Prof. Broom (Kevin Trainor) then uses his .45 sidearm later to protect Broom from the advancing Kroenen. Many of the soldiers also use their .45s when they first see Hellboy.
Glock 17
One of the guards in the museum uses a Glock 17 shoot Kroenen.
U.S. Firearms
M1 Garand
Sgt. Whitman (Angus MacInnes) and several other soldiers use M1 Garands during the opening sequence.
M1 Carbine
A few of the soldiers use M1 Carbines during the opening sequence.
M1928A1 Thompson
A US soldier can be seen using an M1928A1 Thompson noted by the stick mag and the top mounted bolt.
German Firearms
Karabiner 98k
The German soldiers are mainly armed with Karabiner 98k rifles.
One of the German soldiers can be seen patrolling the area with an MG42 in hand during the opening scene.
Support Weapons
M79 Grenade Launcher
An M79 grenade launcher can be seen in Hellboy's arsenal case. Has "FIGHT ARIEL" written on the side. Possible reference to comics?
Mk. 2 Hand grenade
Sgt. Whitman tosses two Mk. 2 hand grenades over cover towards a German scientist who responds "Granate, Granate!" before being blown into the vortex(and letting out a Wilhelm scream) in the opening scene.