I recently acquired a Mossberg Shockwave, and found that the grip was a tad bit slippery. I busted out some good old 3M ladder tape that I had, and cut out some shapes for the grip. I figured I would share this here, because why not. :P Now this certainly doesn't substitute the tried and true traction grips or talon grips. If you are looking for quality, those are what you should get. But if you are cheap like me, and have a roll of grip tape laying around already, I made a template for the DIYer (let's see if I can upload a PDF to ODT). This is the result of my endeavor. The best part of any grip tape, it can be removed or replaced later.
