I got my RWS 460 about a month ago and I have a bunch of rust colored grease on the chamber now. Cocking sounds gritty and I would like to clean and lube this part. I would preferrably send the gun off for a professional tune but I don't know anyone. If anyone can point me in the right direction or refer me to someone that can tune a 460 magnum, I would greatly appreciate it. I read on these forums that John in PA does good work but I don't know how to get in touch with him. Replies appreciated.

All the 460s have that brown grease.

You could send it off and have it 'tuned' - or DIY, save the cost, get 98+% of the benefit, and LEARN something.

There is not much to it, really; disassemble, degrease, file the interior edges of the cocking slots on the receiver tube, lube (MINIMAL - Less is BETTTER!) and reassemble. You can find all sorts of info on these porcedures with some searches. The only "tricky" bits on the 460 are the cocking lug removal (allen plug on the front of the compression tube) and the jiggling you will need to do to reintall the small spring used to tension the breech seal. If its not nicked or cut, the stock Diana piston seals are quite as good as anything else, and the stock spring delivers fine power; no need to replace either.