Hellsing, like many anime, started as a manga series. Written by Kouta Hirano, the story revolves on an English organization called Hellsing, based on the original Van Helsing. The organization's mission is obvious; to hunt down vampires and other supernatural threats to England.
The first anime adaptation of the franchise was in the form of a 13 episode long television series from Gonzo Studio in 2001. The result was somewhat tame compared to the manga, and wound up moving past all of the material that Hirano had written approximately halfway through its 13 episodes. This meant that Gonzo was forced to fabricate their own ending which differed greatly from the manga. The series also suffered from uneven animation quality as a result of budget issues. An OVA remake, Hellsing Ultimate, followed the original manga's storyline.
The following weapons were used in the anime series Hellsing:
Hellsing Arms .454 Casull
Alucard's signature weapon is the Hellsing Arms .454 Casull (unofficially known as the "Joshua"). This weapon is the first custom handgun made by Hellsing, and was specifically designed by Walter. It's essentially a very big semiautomatic pistol, with a length of 39cm. It's chambered for the mighty .454 Casull round, which finds use primarily in hunting large game, such as deer and bears. Of course, these bullets are special, being made out of silver obtained from melted holy relics, with an exploding property as well, making for a rather devastating cartridge against the legions of the night. The Casull is believed to be based upon the Colt 1911 (or its variants like the longslide), however it also bears a resemblance to early model Colt pistols. In some close ups, one may note that the hammer is never fully cocked, indicative of either a double action or fast-action mechanism similar to the Daewoo DP51. The lengthy barrel and slide gives this gun incredible accuracy, and the weight at the front of the gun makes the massive round significantly more controllable. Something this extreme suits Alucard perfectly.
Trivia: During the flashbacks to World War II (specifically 1945) seen in much of the OVA's promotional material, Alucard is seen using this same weapon. This is anachronistic, as the .454 Casull round was developed in 1957.
Alucard's second handgun is the Jackal, which was also made especially for him. The Jackal was made by Walter after Alucard's first encounter with Anderson - in fact, it likely was specifically designed with him in mind, considering the phrase "'Jesus Christ is in Heaven Now'", a variation on a similar statement on Anderson's equipment, is engraved on the side. The Jackal has an overall length of 39cm (the same length as the Casull), is made from pure silver, and weighs 16kg. The slide covers the entire top frame, and there are thus no creases or lines on the top part of the gun, making room for the engraving. Obviously, no human could possibly use this gun without being blown away by it. The breech also faces the left, instead of the right, so it's more of a sister gun to the .454, though its magazines can hold about the same amount of bullets that the Casull is capable of. The bullets are different as well, being a bigger 13mm, with a gold casing, a reinforced core for armor penetration, a mercury explosive and each bullet being baptized. Compared to the Casull, the Jackal is distinctly lacking in terms of aesthetic features, and is devoid of any contours on the side or frame save for the grip. This suggests that Walter designed the weapon immediately after Alucard's encounter with Anderson and did not have time to improve its appearance.
This gun is of fantastic proportions. No 13mm round was ever produced. A .50 alone would equal 12.7mm, meaning each bullet must be manufactured by Hellsing alone. It's curious as to how this weapon can weigh 16kg when a full size 7.62X51mm machine gun only weighs 11kg, the weight is probably necessary to control the 13mm rounds, though with a gun this heavy you could probably fire a .50cal BMG round and still have the same desired effect.
Heckler & Koch Mark 23
Seras's sidearm is a Heckler & Koch Mark 23 in the original television series. It was replaced by a more sensible P226 in the OVA.
Integra uses a Walther PPK on the shooting range and against Yan in the meeting room in the TV series. It is loaded with a fictive incendiary mercury round.
Luke Valentine's sidearm is a Walther PPK/S concealed within his sleeve in episode 6.
A Beretta 92FS is seen the hands of a Hellsing turncoat in the TV series.
Integra is seen firing a Beretta 93R at a shooting range in the TV series.
Customized FN P90s
Yan Valentine wields a pair of heavily modified FN P90s. Both have part of the stock and handle removed, with a more conventional pistol grip placed instead. A silencer has been added, along with an underbarrel laser dot sight. Of course, his eye sigil also adorns the side of the weapon. In the TV series, one had a long scope attached to it and the other a red dot sight.
Heckler & Koch MP5A3
Both Hellsing members and London police officers are seen with H&K MP5A3s.
Skorpion SA Vz 61
One of the vampire teens in the TV series uses a Skorpion SA Vz 61. In the OVA, it was replaced with a Micro Uzi.
Enrico Stivaletti grabs a Steyr MPi81 from a police station in the TV series when he attempts to escape.
Seras's Rifle (Hellsing Anti-Midians 13.7mm)
This unnamed rifle was used by Seras before she was given the Hallconnen. She also used it with a drum magazine later on in the TV series. This weapon is clearly manufactured by the Hellsing organization for anti-vampire combat, though it is uncertain who was intended to wield it before Seras joined. The stock engraving reads "Anti-Midians" and gives the caliber of the round as a massive 13.7mm.It's also mentioned that it's extremly heavy,as it weighst 50 kilograms unloaded.
"Mare's Leg" M1 Garands
Luke Valentine's weapon of choice is a pair of extremely short M1 Garand rifles. The stock is cut down and the barrel and gas piston almost halved in length, making them resemble a "Mare's Leg" short pistol / carbine. Such a conversion in real life would essentially require a complete rebuild of the working parts of the rifle, since the Garand's operating piston is a rod that runs almost the entire length of the barrel, and a Garand gas piston shortened this much while firing the same round would probably explode.
The M16A1 rifle is used by Hellsing forces in the original TV series.
Accuracy International Arctic Warfare
Both Seras and assorted Hellsing members use Accuracy International Arctic Warfare sniper rifles. Seras was told to not equip hers with a scope because, as a vampire, she can see farther than any human could.
Ithaca 37 Stakeout
An Ithaca 37 "Stakeout" is taken by Enrico Stivaletti as he tries to escape from a morgue.
Seras Victoria gets this fictional cannon later in the series. This is the weapon that Walter gives Seras in episode 5, "Brotherhood" and the OVA shows the same scene as well, in the 2nd episode. This weapon's name is rendered as "Hallconnen" but actually pronounced "Harkonnen" and is a reference to the primary antagonists of the novel Dune, House Harkonnen (the spelling discrepancy is the result of the Japanese pronunciation of "Harkonnen"). The cannon is almost hilariously oversized, but Seras soon handles it like a normal rifle because of her strength as a vampire. Walter says that it uses depleted uranium shells, and high explosive rounds. The Harkonnen fires 30mm cannon shells.
This is effectively an artillery piece scaled down to so a person can hold it like a rifle, which Seras does from time to time. It operates using a traditional breech-action system.
Incognito's Armscor 40mm MGL
This is a fictional multi-shot grenade launcher based off the South African Milkor MGL. The weapon does not fire normal explosive grenades (though a wide range of ammo can be used, Incognito loads them with special shells containing multiple dart-like objects that have some magical property, which Alucard describes it as "magic from the dark continent"). As with Incognito himself, this weapon only appears in the television series.
Luke Valentine uses a M202 FLASH to break into the Hellsing compound in the TV series.
Seras uses an Arwen 37 grenade launcher several times in the TV series.