Rebel Rifleman: Riflemen serving under the Rebel Army. They are frequently found hiding behind shoulder-high barriers (making them difficult to hit without using explosives) or in groups. When compared to bazooka Rebels, they are somewhat more flexible in movement options (they can crouch and occasionally even run around unrestricted), but can only fire horizontally. They also have the option of using a melee attack, which swings much faster than other enemies', making them extremely dangerous up close. Sometimes their animation shows them struggling to operate their rifle's bolt, then smacking their rifle against the ground a few times before being able to cycle it, hinting at their weapon being somewhat unreliable.
Amadeus Syndicate Rifleman: Riflemen serving under the Amadeus Syndicate. Unlike other riflemen, they fire with AR-10 Autorifles stolen from the Regular Army. they can shoot diagonally, but the bullets move relatively slow. Beyond that, they have the normal range of attacks standard to soldiers. They are only found in Mission 6 of Metal Slug 4.
Ptolemaic Sniper: Snipers serving under the Ptolemaic Army. Their rifles have a higher rate of fire when compared to Rebels, and have been modified with scopes. They are generally found hiding in bushes or beneath crates. They are only found in Mission 2 of Metal Slug 5.
The rifles used by the Rebels could be based on the German Kar98, while the rifles used by the Ptolemaic Snipers might be based on the American M1903 Springfield or the Japanese Type 99 Arisaka.