The ornamental design for a magazine well extension, as shown and described.
FIG. 1 is an isometric view of a magazine well extension;
FIG. 2 is a front elevation view of the magazine well extension of FIG. 1;
FIG. 3 is a rear elevation view of the magazine well extension of FIG. 1;
FIG. 4 is a right side elevation view of the magazine well extension of FIG. 1;
FIG. 5 is a left side elevation view of the magazine well extension of FIG. 1;
FIG. 6 is a top view of the magazine well extension of FIG. 1; and,
FIG. 7 is a bottom view of the magazine well extension of FIG. 1.
In the drawings, all areas and broken lines immediately adjacent and within the solid line edge of the article visible in views of the top and bottom of the magazine well extension depict portions of the article that form no part of the claimed design. The exterior sides of the magazine well extension within the dot-dash-dot broken line boundaries in the drawings are not included in the claim.