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.
Jackal
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 it's 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.
SIG P226
A SIG-Sauer P226 is seen in the hands of Seras during her time as a police officer. Integra also uses a P226 as her sidearm as choice, stating that it is loaded with silver Heavy Explosive rounds.
Pip uses a Glock with a suppressor in the OVA to assassinate the corrupt police officials working with Millennium.
Luger P08
In the OVA 10 the Major uses a chrome plated luger with black grips (whitch is handed by an automatic machine) in an attempt to execute a disobedient officer. Who is later killed by his mates due to the Major's terrible accuracy.
Tokarev TT-33
During Alucard's dream we can see the Major wearing his SS uniform with a TT-33 being pointed to his head. A TT-33 pistol is also used by a Russian officer who executes the major in the streets of Berlin after his squad found him.
Iscariot Pistol
Walther P38
In the last Ova the Major pulls out a Walther P38 in a last attempt to kill Integra, as usual he misses but eventually hits her, this was enough to satisfy him.
Walther PP
After being resurrected during in the final battle against the Hellsing traitor, Luke Valentine draws concealed a Walther PP concealed within his sleeve.
Submachine Guns
Customised 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. Both weapons also use sniper scopes instead of the P90's built-in reflex sight in the OVA, which is a very odd choice of optics for a PDW.
It is also an odd bit that Yan's P90s do not act like they are silenced, as noted by the muzzle flash and the loud rapport of his weapon while firing.
Heckler & Koch MP5A3
Both Hellsing members and London police officers are seen with H&K MP5A3s.
Heckler & Koch MP5K PDW
Yan Valentine's ghouls are all armed with H&K MP5K PDWs equipped with PVS-14 night vision scopes, suppressors, and jungle-style magazines although the ghouls using riot shields do not have the scope mount. The This same design was also seen in the hands of a few police officers.
Much like Yan's P90s, the suppressors mounted on the MP5s do not seem to have any effect on the weapon.
Beretta PM12S
The Beretta PM12S was seen in OVA. It is possible that these are Taurus PM-12s (a licensed copy of the Beretta PM12S made in Brazil) since these are used by a Brazilian police SWAT team.
Micro Uzi
A Micro Uzi was see seen in the hands of a vampire teen in the OVA.
Uzi
A police officer can be seen wielding an Uzi during the first episode of the OVA.
MP40
The Millennium Organization's army of Nazi vampires are largely equipped with MP40s.
Thompson M1928
A M1928 Thompson can be seen in Alucard's dream sequence at the beginning of the 5th OVA. The entire dream revolves around films based on Frederick Forsythe novels. The Thompson is seen during a reference to The Fourth Protocol.
Rifles
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 and OVA. 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.
Sawed-Off M1 Garands
Luke Valentine's weapon of choice is a pair of sawn-off M1 Garand rifles. In the television series, both the stock and barrel/fore-end have been cut down, effectively turning these rifles into high-caliber pistols. In the OVA, only the barrel and fore-end have been cut, and the stock has been left intact.
Several M16A2 rifles are used by Brazilian solders/officers in an (unsuccessful) attempt to kill Anderson.
L85A1
Traitorous British soldiers in the OVA are seen wielding L85A1 service rifles. Another is seen in the hands of a member of the Wild Geese during Zorin's assault.
Norinco Type 84S
Two members of the Wild Geese in the OVA are armed with Norinco Type 84S rifles.
AK-74
Most of the Wild Geese in the OVA are armed with AK-74 rifles. It is also the preferred weapon of Pip Bernadotte, the captain of the Wild Geese mercenaries.
AKS-74U
Several members of the Wild Geese use AKS-74U rifles while working for the Hellsing Organization.
Sturmgewehr 44
Several of the Nazi vampires in the OVA are armed with Sturmgewehr 44s.
In OVA 9 Hienkel takes an SVD Dragunov from one of his comrades to take revenge for the death of Yumie. It is seen with medical bandage round the wooden handguard
Machineguns
MG42
Seras Victoria and several Millenium soldiers are seen with MG42 during OVA 10.
Heavy weapons
Harkonnen cannon
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.
The Mk 47 Mod 0 Grenade Launcher is used by the Wild Geese to defend Hellsing manor against Millennium's forces with devastating effect.
Panzerfaust
Millennium's army of Nazi vampires in the OVA makes liberal use of a multitude of Panzerfaust launchers.
Panzerschreck
Several Nazi vampires carry Panzerschrecks during the attack on London.
Phalanx CIWS
A CIWS Phalanx on the deck of the captured British aircraft carrier is used against Alucard's Blackbird in the OVA.
Harkonnen II
The Harkonnen II is a fictional weapons system consisting of a pair 30mm automatic cannons coupled with an incredibly large ammunition supply. Seras uses these weapons to barrage Zorin's zeppelin with an overwhelming display of firepower. The ammunition containers are detachable, and Seras is seen using Harkonnen III without them, though she quickly runs out of ammo.
Vladimir
Described as a "Wide area saturation, high explosive incendiary grenade launcher", the Vladimir is a set of fictional muzzle-fired grenades that are part of the Harkonnen II weapon system. Seras uses these to deliver the final blow to Zorin's zeppelin.
88mm gun
When Seras Victoria was ordered by Integra Hellsing to kill the Major behind a wall of highly resistant bulletproof glass that even the Harkonnen could not breach with multiple shots; she resorts to tearing out one of the Deux Ex's 88mm flak guns, which succeeds in one shot.
Wall of Guns
Seen in the first episode of the OVA. It consists of
a Sig P220 series
an AK-74
an M16 with the three-pronged compensator [drawn upside down]
an M1911
an M16 with the birdcage compensator
a Colt Python
Franchi LM57
Sten MkII
Lee-Enfield No4 (With bayonet attached)
Near the end of the wall of guns several muzzle-loading muskets, one with a bayonet attached, can be seen.
And all these were pointed at Alucard, but were still not enough firepower to take down one of the most powerful vampires in existence.