Agatha Christie's Poirot - Season 1
First season of Agatha Christie's Poirot contains 10 episodes: "The Adventure of the Clapham Cook", "Murder in the Mews", "The Adventure of Johnnie Waverly", "Four and Twenty Blackbirds", "The Third Floor Flat", "Triangle at Rhodes", "Problem at Sea", "The Incredible Theft", "The King of Clubs", and "The Dream", all adapted from short stories.
The following weapons were used in Season 1 of the television series Agatha Christie's Poirot:
Donovan Bailey (Nicholas Pritchard) holds a revolver in "The Third Floor Flat" (S01E05). The gun is seen only from the muzzle and is hard to be identified. The size of the muzzle and chambers allow to guess that it's a small caliber weapon. There is a possibility that it's the same gun that is used in "The Dream" (S01E10) (see below).
Colt compact revolver
In "The Dream" (S01E10) a compact revolver is seen in hands of Hercule Poirot (David Suchet) who then gives it to Captain Hastings (Hugh Fraser). The revolver is some Colt model; Colt New Pocket seems to be a good guess.
MAB Mode A
In "Murder in the Mews" (S01E02) a nickel plated with pearl grips MAB Model A pocket pistol is seen in dead hand of Mrs Barbara Allen (uncredited) who is supposed to commit suicide.
Italian carabiniers on Rodos carry holstered handguns. The shape of most holsters allow to guess that Beretta pistols, like Beretta M1934, are inside, but it's only a guess.
Bolt action rifle
A bolt action sporting or hunting rifle is briefly seen in the Scotland Yard laboratory in "Four and Twenty Blackbirds" (S01E04).
Carcano M91/38 Cavalry Carbine
Italian soldiers and carabiniers on Rodos (the island belonged to Italy during Interbellum) carry Carcano M91/38 Cavalry Carbines in "Triangle at Rhodes" (S01E06).
Double Barreled Shotgun
Hispano Mk II
Spitfire IX that appears in "The Incredible Theft" (S01E08) in the "role" of a brand new fighter aircraft is armed with two Hispano Mk II autocannons.
The plot item in "The Incredible Theft" (S01E08) is a brand new fighter aircraft - a prototype for Spitfire, nicknamed "Mayfield's Hawk". Spitfire IX appears in the episode in this "role".