MCRP 12-10B.1, page 203

b. Walls. When firing from behind walls, a Marine should fire around coverCnot over it (Figure A-52). Marines in this situation should be able to fire from the right or left shoulder. When firing from behind cover, a Marine should remain far enough back from that cover so that the weapon does not extend beyond it. This aids in weapon retention by ensuring that no enemy on the other side of the wall can get control of the barrel. Figure A-52. Firing Around Cover c. Windows. In a built-up area, windows provide convenient firing ports. A Marine should avoid firing from the standing position because it exposes most of his/her body to return fire from the enemy and could silhouette him/her against a light-colored interior beyond the window. This is an obvious indicator of the firer’s position, especially at night when the muzzle flash can easily be observed. When using the proper method of firing from a window (Figure A-53), the Marine is well back into the room to prevent the muzzle flash from being seen, and he/she is kneeling to limit exposure and avoid silhouetting himself/herself. Figure A-53. Firing From a Window A - 42 MCWP 3-35 .3