For a short while I used Grease on 1911's ( just to experiment) however I did not like the unburnt powder residue and debris it picked up while shooting them. I went back to oil as I have used for most of my 40+ years of shooting Pistols.

NOTE:
Don't know all the pistols you guys own but I have never seen an instruction manual for a pistol that called for grease to be used. I have always seen "oil" as the specified lubricant. I am not saying no pistol manual specifies grease - I've just never personally seen one that did.