Any quality oil or grease is fine. I believe the traditional lube in England is/was petroleum jelly (Vaseline). Doesn't make much difference IF you frequently clean your gun. Grease tends to attract more dirt but doesn't migrate to other parts as oil might. With either just keep it light. I often see it gooed and smeared on as though it was an axle on a wagon. If you can see it you probably have too much on, IMO.

When an old man dies a library burns to the ground. (Old African proverb)