I have an $8 one pound can of Mobile 1 Synthetic Wheel Bearing grease that I've been using on my semi-auto rails for years with no problems and still have 7/8 of the can left. The synthetic doesn't attract dust as bad and stays in place for a long time.
I was using Rem-Oil w/ Teflon on the actions until I ran out and tried the wife's Singer Sewing Machine All Purpose Machine Oil for under $3 for four ounces. Works perfectly.
"A free people should have sufficient arms and ammunition to maintain a status of independence from anyone, including their own government. ~ G. Washington