Let me add one thing. Be careful at reassembly to use a lube that doesn't get thick or sticky. Lots of guys have sprayed WD-40 into guns only to find, some time later, that it has gummed up and dust or fouling is held in place by it. It is good for loosening, water displacing (what the WD stands for), and short term rust prevention, but it is not a good wear preventing or high pressure lube so it should, in turn, be displaced by a proper gun oil after it is used on guns.
There are a lot of good lubes out there, and you want to use what you get sparingly so the cost isn't usually an issue if you spread it out as added cost per shot during the lifetime of the lube container. Nonetheless, good old inexpensive, homemade
Ed's Red is an excellent overnight soaking solvent for fouling crud cleaning (followed by used toothbrush scrubbing the next day) and after wiping off, won't gum up gun internals. The transmission fluid in it withstands temperatures and pressure well. It is a good place to start, even if you decide to use Sprinco Machine Gun Lube or Wilson Ultra lube or some other high end product for a little extra slickness later.