Water Rats was an Australian police drama series centered on a pair of detectives in the Sydney Water Police running for 177 episodes between 1996 - 2001.
Smith & Wesson Model 10 with three inch barrel
The Smith & Wesson Model 10 was the then standard issue revolver of the NSW Police Force. It was used by almost all the characters in the series.
Smith & Wesson Model 10 Heavy Barrel
In the episode "In The Family Way" Detective Sergeant Jack Christey has his pistol wrestled from him and used by a boat hijacker to shoot him.
The SLR is used with and without various types of scope by NSW Police State Protection Group officers.
In part two of 'Double Play' (1998) an M16A1 with what appears to be a Cobray 37mm launcher is used for some reason by one of the NSW Police State Protection Group officers during a shoot out with armed robbers. No grenades are fired from the weapons during the scene.
Cobray 37mm Launcher
Never fired but fitted to M16A1.
Unknown CAR15 variants
In part two of 'Double Play' (1998) various CAR15 and XM177E2 styled assault rifles are used by State Protection Group officers.
Remington 870 Field gun
Shortened barrel Remington 870 Fieldguns used by tactical officers.
Throughout the series the SPG officers can be seen with what appear to be MP5 Variants at first, but on closer inspection appear to be modified prop guns, almost a combination of an HK94 'Chopped & Converted' barrel inside an MPSD3 hand-guard for some reason. These MP5 variants are never actually seen to be fired during the series thus it is possible they are "non-guns".
In the episode "Double Play" a tactical officer exits an unmarked 4WD armed with what appears to be a faux MP5. When the tactical officers open fire only CAR-15/M16A1's and shotguns are seen in the hands of the officers.
Used in a drive by shooting by criminals in the final episode.