I have a new Remington 870 shotgun with the Knoxx Spec Ops stock on it. Remington is now selling the package with the model number 81400. I love the recoil reduction on the stock but I'm having trouble with the chambering of a shell after shooting a round. When I load 6 into it, at least once it will fail to load a round. Another pump and it will load and shoot. On the times it doesn't load one, I can usually tell right after I fire it. It seems like the forestock releases too fast (?) and the next shell won't load. I've already sent it to a Remington service center once and they said they deburred it and polished the chamber. It still fails to load a round at least once in 6 shots. I carried an 870 in 34 years of federal law enforcement so I know my way around these, but I'm stumped. Remington told me to send it back to the factory, but I wanted to see if anyone else out there has either had this problem or have any idea what it might be. Thanks.