The M42A Scope Rifle is a 10mm pulse action semi-sutomatic rifle employed as the primary sniper weapon of the United States Colonial Marine Corps. This rifle is a key component of battalion operations; its long range and precision extending the tactical zone of control by up to a kilometre or more, subject to local terrain. The rifle is issued on a scale of one per company, though it is normally held for use in a battalion controlled pool of up to four Scout Snipers.
The M42A is configured in a bullpup configuration, with a casing of titanium-aluminide over a duratel frame. Up to six plastic spacers are supplied for adjusting the butt length to the individual Scout-Sniper. An overhead rail carries a removable folding bipod clear of the barrel. The internal mechanism is designed to have a high degree of commonality with the M41 - using the same rotating breech and feed - though it is chambered for the match standard 10mm x 28 caseless round. The barrel is free-floating with a right handed twist and is contained within a protective shroud and receiver housing. Barrel options include a flash suppressor or a muzzle brake for long range shooting. Ammunition feed is from a 16 round Match magazine inserted beneath the stock of the rifle, behind the thumbhole of the pistol grip. An optional iron sight can also be fixed to the barrels overhead rail.
The match-standard batched M252 HEAP round has a maximum effective range of 2950 metres. A long-range stabilised ball round is also available, with an effective range of 3800 metres. The factory standard M250 Smartgun round can be used with no adaption, though it has an effective range of well under 2000 metres. Fusing for the M250/M252 ammunition is controlled from a separate selector switch.
A combined multi-spectral 20× sensor scope is mounted on top of the receiver. The scope display show a composite image based on visual, infrared and electromagnetic emissions. The scope display can be augmented by input from the local sensor matrix via a digital comms broadcast or direct optic cable link. Motion trackers, ground radar, lidar and IR sensors may all be linked into the rifle; furthermore, the optional PARGET control system - exact details of which are classified - is apparently able to connect the rifle into local Sentry Gun matrix, allowing the Scout-Sniper to redirect Sentry Gun firing arcs when required.