No stock buttstock shell holder - Allen Buttstock Shell Holders

Meh! This Buttstock (Hee, Hee, Butt-stock) shell holder slips and slides worse than my ten-year-old underwear. As soon as I installed the buttstock shell holder I saw that one end, the end closest to the trigger area, was really loose and the other end, the end closest to the buttpad, held firmly. After sliding five shells into the holder, it did tighten up, but not enough to keep the shell holder in place. The weight of the shells makes it want to slide under the stock, poking me in my chin and making the buttstock awkward to get a good cheek-weld.