The marksman carbine is a semi-automatic, medium-power rifle with a 20-round magazine. Mounted with an enhanced-zoom scope that shares the same mil-dot reticle as the anti-materiel rifle and sniper rifle, but its barrel and magazine appear to have a stainless steel coating. It is highly accurate and deadly at long range with a Gunsskill of 100. Additionally, it has a very low Action Point cost of 14, lower than most pistols as well as being the lowest out of any rifle in the game.
The marksman carbine can fire a total of about 1,995 standard rounds, the equivalent of 100 reloads, from full condition before breaking.
One of them can be found near Securitron de-construction plant on the pipe to the east from the main entrance. Just follow the pipe until finding a spot in which the player character can jump up onto the pipe.