The bolt rifle is the basic weapon of the Ultramarine. The bolder has unlimited ammo, has a moderate range and it does decent damage. The bolt rifle serves as the basic weapon, but the secondary weapons allow the player different tactical options.
The combat shotgun is a secondary weapon that scouts can use. It does little damage at long-range, but is a good close range co weapon that can be used to eliminate multiple enemies close to your unit. The sniper rifle is a scout weapon that allows a character to take out an enemy unit from afar.
Plasma rifles are available only to space marines of terminators. Plasma rifle have a s shorter range than the bolt rifles, but they excel at removing walls and other obstacles. The rocket launcher, long-range area of effect weapon, becomes available later in the game.