Accu-wedge - Kleen Bore Accu-Wedge AR-15/M16 Buffer System

I installed this, or tried to, in my S&W M&P15. The base of the wedge was so thick, the rear retaining pin would not even start to feed through the hole. After shaving down the base, the canted angle of the back of the wedge was so inconsistent with the locking block of the upper receiver, that it was smashing the wedge into the lower receiver. I cut down the back of the wedge, and still no luck getting the upper and lower to mate correctly. I shaved a piece about 1-2mm thick off the base, jammed hat in the lower, and it worked better than the actual wedge itself. I've installed these in other mil spec rifles before and have never had any issues. Perhaps it is because they were military issue and had thousands of rounds through them, rather than a BNIB AR15. Either way, I was extremely disappointed for a piece of equipment so simple to have so many problems. Good thing it was only a couple of bucks!