New Dominion Tank Police is a 6 part OVA based on the 1985 manga series Dominion: Tank Police written by Masamune Shirow (creator of Ghost in the Shell, Black Magic M-66 and Appleseed).
The following firearms are used in the anime OVA New Dominion Tank Police:
Brenten uses a custom 8 inch, stainless steel Colt Python revolver known as "The Castigator". It boast a wide range of custom features, including custom frame contours, texturing on the front of the triggerguard, a custom barrel weight and compensator. and a ring hammer. Oddly, the revolver is drawn as being built from a Smith & Wesson Model 66 during the opening credits, as denoted by the S&W-style cylinder release.
This reoccurring design is first seen in Act 1, where it is outfitted with a sound suppressor, and then is featured more prominently in Act 4. The design draws heavily from the S&W 39 series pistols.
Leona Ozaki's weapon of choice is a MAC-11 submachine gun chambered for .380 ACP/9mm Short. She occasionally uses non-lethal "stun rounds" (likely rubber bullets) to subdue criminals. Another MAC-11 is seen during Act 2 in the hands of a criminal during a flashback sequence.
One of he criminals in Act 1 uses a H&K MP5K with a ridiculously large sound suppressor. Another MP5K in the same configuration is seen in Act 4. A single unmodified MP5K is seen in Act 5 in the hands of one of the Mayor's bodyguards.
Several AK-47 rifles can be seen throughout the series. At least one of these rifles belongs to the Tank Police Squad. More AK-47s can be seen in Act 5 in the hands of various criminals during a crime wave.
Nam is seen cleaning several Seburo MN-23 rifles. Another MN-23 makes a brief appearance in Act 4 in the hands of a criminal. The MN-23 was originally designed by Masamune Shirow as a commissioned design for Poseidon.co.jp (a manufacturer of replica resin kits of anime and manga weapons) as a cosmetic upgrade for the then-new electric airsoft version of the FAMAS assault rifle produced by Tokyo Marui. The original "backstory" of the gun specifies that it was intended as a less-than-lethal police riot control weapon, but since then has been used on multiple occasions (usually in adaptations of Shirow's manga) as a 5.56mm assault rifle. New Dominion Tank Police is the first instance of the MN-23 making an appearance as an actual assault rifle as opposed to a riot-control weapon.
During Act 3, several Newport City Police Officers are seen using a fictitious bullpup rifle. The weapons aesthetic design seems to be primarily inspired by the Mossberg Bullpup shotgun.
One of he criminals in the first episode uses this fictional fully automatic shotgun. The weapon is fed from a drum magazine and has a heat shield covering the barrel.
