Skurge (Karl Urban) keeps and wields dual M16/SP1 rifles with birdcage flash hiders. Aside from affectionately referring to them as "Des" and "Troy", he mentions acquiring them from Earth, specifically Texas, USA. The use of the M16 rifles are a direct reference to Skurge's appearance in the comic books.
M16 (SP1) fitted with A1-style birdcage flash hider (to imitate the M16A1) and 30-round magazine - 5.56x45mm
Skurge (Karl Urban) holds "Des" and "Troy" after pulling them out from his "stuff" pile.
Dual M16/SP1 rifles are seen in the hands of Skurge (Karl Urban) after firing on board the Statesman. Note the right rifle's bolt release button is sticking out and the left rifle's bolt is locked back indicating the rifles are empty, however Skurge is able to fire both of them again without reloading.
In a scene from the trailer, Skurge fires the SP1 rifles.
M16A1
In a continuity error, the M16/SP1 rifles used by Skurge turn into M16A1s with forward assists.
M16A1 Assault rifle - 5.56x45mm. Used by the United States military from 1967 to 1989.
The rifle in his left hand has a forward assist.
Closeup of the rifles in use. The muzzle flashes are a CGI effect as the rifle seen really isn't actually firing, as noted by the fact that the dust cover remains locked in place. Both rifles also have the 3 prong "duck bill" flash hiders.
Skurge uses the rifles.
Skurge (Karl Urban) holds the M16A1 after it runs dry.