Dig two trench-shaped grenade sumps. Place one at each end of the position. Make the trenches as wide as an entrenching tool blade, as deep as the entrenching tool, and as long as the position is wide.

Slope the floor toward the sumps. The slope should be steep enough so that a grenade thrown into the position will roll into one of the slumps.

When using flank overhead cover, rather than center overhead cover, place the grenade sump in the center rear of the fighting position floor.