Blister packs affixed to B-25 fuselage

In the Pacific, the Army wanted more punch from their B-25s. A quartet of forward-firing guns was added near the nose. North American Aviation called them “fuselage gun packs” and “cheek packs,” but in the field flyers almost always called “blister packs.” The guns and their weighty ammunition near the nose threw off the plane’s center of gravity so they were moved aft of the cockpit in later iterations. The thundering guns punched holes in the thin aluminum fuselage so blast tubes and reinforced sheet metal plates were installed as protection. The new gun packs gave the Mitchell a wicked punch when attacking ground targets.