Most of the time, the Maaskantje police officers are carrying the Walther P5 as a standard weapon.
Unidentified M1911A1 variant
After his discharge the Maaskantje police officer steals at least two pistols from the gun locker. He hands out one to a prisoner he tries to recruit for his crusade, but the prisoner decides to kill himself rather than help a cop. The gun appears to be some kind of customized M1911A1 variant with several external parts as sights etc. missing.
Police snipers on the a roof, waiting for the New Kids to show up. The Maaskantje officer on the left is using an WWII era model M1 Carbine with 30-round magazine (or possibly an automatic M2 carbine, but no fire selector swith is possible to tell for sure).
Remington M40
Police snipers on the a roof, waiting for the New Kids to show up. The reinforcement officer on the left is keeping a Remington M40 at ready.
Karabiner 98k
Rikkert is armed with a Karabiner 98k after the New Kids looted the weapon stash.
Submachine Guns
Beretta M1938
Gerrie shows the Beretta M1938 to Richard, after he fired it at his friends.
MP28/II
MP40
The Maschinenpistole 40 or MP40 is used by some of the New Kids and by Manuela in the final shootout.
M1A1 Thompson
The take-out owner receives an M1A1 Thompson from Richard to protect his business and Manuela's children. He later uses it in an ambush.
A MG42 is also used by Barry in the final shootout.
MG15
In the background during the scene in the weapon stash, an MG15 machine gun in an anti-aircraft application can be seen.
Miscellaneous
Pump action shotgun
Also in the weapon stash we see Gerrie carrying a pump action shotgun.
M72 LAW
Gerrie uses a M72 LAW to take out an approaching police car. There is a inconsistency in the movie, since he fires the same M72 LAW two times. In real life it's a single-use weapon.