The ornamental design for a modularforendsystem for firearms, as shown and described.
FIG. 1 illustrates a perspective, side view of a new design for a modular forend system for rifles;
FIG. 2 illustrates a right side view of a new design for a modular forend system for rifles;
FIG. 3 illustrates a left side view of a new design for a modular forend system for rifles;
FIG. 4 illustrates a rear view of a new design for a modular forend system for rifles;
FIG. 5 illustrates a front view of a new design for a modular forend system for rifles;
FIG. 6 illustrates a bottom view of a new design for a modular forend system for rifles;
FIG. 7 illustrates a top view of a new design for a modular forend system for rifles;
FIG. 8 illustrates another right side view of a new design for a modular forend system for rifles; and,
FIG. 9 illustrates another bottom view of a new design for a modular forend system for rifles.
The broken, dashed lines shown in the various figures depicting embodiments of the invention are included for the purpose of illustrating environment and do not form any part of the claimed design.