FIG. 1 is a left side top perspective view of a lower grip housing for a firearm showing our new design;

FIG. 2 is a right side perspective view of the lower grip housing of FIG. 1;

FIG. 3 is a left side elevation view of the lower grip housing of FIG. 1;

FIG. 4 is a right side elevation view of the lower grip housing of FIG. 1;

FIG. 5 is a top plan view of the lower grip housing of FIG. 1;

FIG. 6 is a bottom plan view of the lower grip housing of FIG. 1;

FIG. 7 is a front elevation view of the lower grip housing of FIG. 1; and,

FIG. 8 is a rear elevation view of the lower grip housing of FIG. 1.

The broken lines showing portions of the design in all figures is included for the purpose of illustrating environment and forms not part of the claimed design.