schmeky,
I had sucess with 80 grit glass bead abrasive from Clarke, it was designed to use with their cabinets, I purchased my abrasive and blast cabinet from the local Tractor Supply store. If you have one in your neighborhood you might call,if they have the abrasive in stock it will save you the shipping.
I used mine to do a badly pitted slide on a SIG 226,but I also Dura-Coated the glass bead blasted slide. If you want the roll markings to remain untouched you can cut "masks" from DYMO plastic label tape, it will withstand the blast .