JWR-I have had issues in the past with p-85's. Either they work well or they don't. I had an old one from a B/O badge Acrolite snare that was bad. It just loosened up all the time. The other one was on a 2000 6.5x14 Brass Edition drum. That one made me mad because I bought it from Interstate Music and I sent it back and they sent me another drum that had a dent in the bearing edge of the bottom of the shell. I bought my Dunnett Stainless Steel shell after that. The first drum sounded so good too. It sounded like Bonham's snare circa Houses of the Holy. I have a p-85 on a Gretsch snare that works fine. I have an older B/O chrome 5x14 Supraphonic and that one works fine too. Tell Memphis Drum Shop and they will send you a new one. If that one doesn't work then I don't know what to tell you. Good luck.

A tip I have used in the past.....give it a try!

Take the faceplate off, and take a small rubberband, take it around the threads numerous times at the top and make it tight.....replace the faceplate, and make sure to tension it into the band....will make it tight, and will not have a problem.

Are you sure it isn't the snare cord giving you fits?

I have had success with using a small drop of the lowest strength thread locking liquid and then working it back and forth a few times -just to increase the friction a bit.