Originally Posted by
TCinVA
Once folks understand that grease is just oil with a binder, and that the oil component creeps, evaporates, and moves leaving nothing but the binder behind that debate usually stops, too. Shotguns are not a great idea for grease because they typically shoot very dirty and the binder will just sit around and collect crud turning it into a lapping compound. No es bueno.
If you need lubrication that doesn't float out when the gun gets submerged in water, grease works. (That's why the M1 Garand called for grease) Short of that, stick to a proper oil.
What I do for cleaning the gun:
Remove barrel, remove bolt assembly, remove piston. Wipe down bolt assembly with a blue towel and some Amsoil firearms cleaner. Use a typical Brownells plastic scrub brush with some of the same firearms cleaner on the recesses where the bolt lugs lock into the barrel extension. Use the still slightly wet brush to scrub the gas piston and the gas piston's housing. Dry the piston and housing thoroughly. (Occasional efforts to de-lead may be necessary if you shoot a lot of slugs)
Once a year or so I'll take the trigger plate out and clean inside the receiver usually using a spray solvent or something to blow a lot of that crud (unburned powder, other debris) out of there.
Cleaning the bore:
Brownell's chuckable shotgun cleaning rod and a tornado brush with a little BoreTech shotgun blend. I usually clean the bore once a year or when my patterns start to get weird.
Lubrication:
I put a drop or two of Amsoil gun lube (made from genuine group 4 base stock) on the neck of the bolt, on the raceway the cam pin rides in, and a drop on each of the bolt lugs. I put a drop on each of the forend welds of the bolt carrier as they ride inside the receiver and experience some friction. (The armorer's manual calls for lubricating these points) I'll also put a drop anywhere else that's shiny from wear.
I put a couple of drops on the recoil spring so it moves freely. (The armorer's manual calls for this, too)
Suitable lubricants:
Use something that doesn't suck or leaves behind sticky residues. RemOil evaporates if you look at it funny. Slip2000 works great...and no, you don't need the EWL stuff. Regular ol' Slip works beautifully.
I personally use Amsoil gun lube, but I put it into individual needler bottles so it lasts a ridiculously long time.