Doomsday

The weapons seen in this movie are:

Vektor SS-77 machine gun

Insted of the British Army issued L7A2 the trooper on the top of the armored vehicle is useing a Vektor SS-77 GPMG. the reason for this was that the Armorers in South Africa where the Movie was filmed most likely didn't have any L7A2s in stock.

SA80

At least one live SA80 was used in the film for a scene when Soldiers fire apon paniced civilians.

The SA80's in this movie are airsoft guns hence the Union Jack sticker at the corner of the butt area. Again, these airsoft guns are used in the movie for the same reason above.

Neostead shotgun

Used in the abandoned hospital

Armsel Striker

An Armsel Striker is seen momentarily durring the crashed APC scene.

Unknown sawed off over/under shotgun

an Unknown over/under shotgun is used to take a DDS agent hostage and is then accidentally discharged into the hostages head.

Winchester 1200

The Woman bathing in the cast Iron tub abord the ship has what looks like a pistol gripped Winchyester 1200.

Prop Sentrygun

A prop Sentrygun is used durring th Border wall scene. it is shown messily destroying a rabbit that gets too close to the wall.

Vektor CR21

Most of the DDS agents carry Vektor CR-1 assault rifles tricked out with flashlights, laser sights, and sound supressors.

M1919A4?

Its possible an M1919A4 is seen in the abandoned hospital mounted on a tripod but is not used.

GAU-19/A

A 3 barrel .50 BMG Gattling Gun is mounted on the SuperFrelon chopper at the end half of the movie.