MCRP 12-10B.1, page 249

Figure B-6. Tactical Use of Holes in Masonry Walls (1) Of all the common building materials, heavy stone is the most difficult to penetrate. The AT4 normally will not penetrate a heavy European-style stone wall. Surface cratering is usually the only effect it will have. (2) Layered brick walls are also difficult to breach with light recoilless weapons. Some brick walls can be penetrated by multiple firings, especially if they are less than three bricks thick. Multiple AT4 rounds fired at the same spot on an 8-inch (double-brick) wall normally produce a loophole. The SMAW produces a hole in brick walls that is often large enough to be a breach hole. (3) Wooden structural walls offer little resistance to light recoilless weapons. Even heavy timbered walls are penetrated and splintered. Multiple AT4 rounds fired at the same area of a wood-framed wall usually produce a human-sized hole. The SMAW has a devastating effect against wood-framed walls. A single round produces a breach hole as well as significant spall. (4) Because of its high velocity, the AT4 may penetrate a soft target such as a car body or frame building before exploding. (5) None of the light recoilless weapons are as effective against structural walls as demolitions or heavier weapons such as tank main guns or field artillery. Of all the light recoilless weapons, the SMAW is the most effective. Military Operations on Urbanized Terrain B - 17