Sears Ted Williams model 300 12 gauge?????

[GatorHunter]

Been looking for any way I can increase the amount of ammo this shotgun can carry. I know it's made only to carry 3 2 below and one in the chamber. When I disassembled for cleaning it looks like it could be manualy done but I am hoping they make modifications for it my searches didn't really turn up much. I do know this gun is similar to the Winchester 1400. Any info on the shotgun modification wise would be great. Thanks,
Gator

[binarybro]

I believe that it's not possible to add a magazine extension as this is where the gas system resides.