When considering small ordinances, which requires less than 1 block of M112?

The correct answer refers to HG's, which indicates hand grenades. Hand grenades are classified as small ordnance and typically require significantly less explosive material compared to other types of ammunition, such as rockets, HEAT (High-Explosive Anti-Tank) devices, or APHE (Armor-Piercing High-Explosive) shells.

When analyzing the explosive content in various ordnance types, hand grenades are designed for close combat and effectively utilize a small amount of explosive to deliver shrapnel and cause damage within a limited radius. This characteristic makes them unique in terms of their explosive requirements, often being less than 1 block of M112, which is a standard reference for measuring explosives.

In contrast, rockets, HEAT, and APHE munitions are engineered for penetrative and destructive capabilities in more extensive combat scenarios, necessitating larger quantities of explosive materials to achieve their intended effects. This distinction clearly positions hand grenades as requiring less explosive charge than the other options presented.