Rockwell (Peter Jeffrey) holds a Smith & Wesson Model 36 with bobbed hammer in the climactic scene in "Treasure Hunt" (S05E09).
Pistols
Browning Hi-Power
Smythe (Jeremy Clyde) finds a Browning Hi-Power in his briefcase in "The Memory Man" (S05E01). Later Pat Harrison (Jeremy Sinden) takes the pistol and uses it in several scenes. Miles Pynsent (John Hartley) carries the Hi-Power pistol in "S.P.A.R.T.A." (S05E06).
Unidentified pistol
In the climactic scene in "S.P.A.R.T.A." (S05E06), Minder (Dinny Powell) holds an unidentified compact pistol. When the pistol falls on the ground during the brawl, Philippa Vale (Liza Goddard) picks it up and then hands the gun to DS Jim Bergerac (John Nettles) who uses the pistol in shootout.
Walther P38
Dr. Anderson (Alfred Burke) holds a Walther P38 in "Poison" (S05E08).
A Flintlock Pistol is seen on the wall in Sir Clive Hamer's estate in "S.P.A.R.T.A." (S05E06). The furnishings of the house is the same that is used in "Ice Maiden" (S03E04), and the pistol is very likely the same prop.
Submachine Guns
Heckler & Koch MP5A3
Heckler & Koch MP5A3 SMGs are used by the members of S.P.A.R.T.A. ultra-right organization in "S.P.A.R.T.A." (S05E06). Sir Clive Hamer (David Calder), the leader of S.P.A.R.T.A., personally holds an MP5A3 during the chase after Philippa Vale and Jim Bergerac. In the final scene the MP5A3 SMGs are seen in hands of the French GIGN (National Gendarmerie Intervention Group) personnel.
Heckler & Koch MP5K
French GIGN personnel also use Heckler & Koch MP5K SMGs in the final scene in "S.P.A.R.T.A." (S05E06).
Uzi
What seems to be an Uzi is also seen in hands of GIGN personnel in the abovementioned scene.
A pair of shotguns that may be single barreled or double barreled are seen on the wall in Sir Clive Hamer's estate in "S.P.A.R.T.A." (S05E06). The furnishings of the house is the same that is used in "Ice Maiden" (S03E04), and these guns is very likely the same props.
Police snipers use Ruger Mini-14 rifles with sniper scopes to shoot monkeys, infected with deadly virus, in "The Deadly Virus" (S05E05). At least one of these rifles is fitted with the aftermarket folding stock.