I have the guy for you, his name is Mark Penrod. I had the same rifle in 416 Rigby and found the action would sometimes bind when cycled fast. I sent it to him and it came back perfect. You can find his contact data on the internet,

A good principle to guide me through life: “This is all I have come to expect, standard lackluster performance. Trust nothing, believe no one and realize it will only get worse…”