The ornamental design for a padded sling for a firearm, as shown and described.
FIG. 1 is a top, front, left perspective view a padded sling for a firearm showing our new design;
FIG. 2 is a top plan view of the padded sling for a firearm of FIG. 1, the bottom plan view being a mirror image thereof;
FIG. 3 is a front side elevation view of the padded sling for a firearm of FIG. 1, the rear side elevation view being a mirror image thereof; and,
FIG. 4 is a right side elevation view of the padded sling for a firearm of FIG. 1, the left side elevation view being a mirror image thereof.
The broken lines showing portions of the design in all figures are included for the purpose of illustrating environment and unclaimed features and forms no part of the claimed design.