The matrial usually runs around .015-.018. If you have a mic take it with you and measure some. They may look at you funny, but if they have been there a while and there are a lot of MLer shooters in your area, they may be used to guys with mics in the fabric dept. :grin: I don't use bore butter, but a lot of people do, You can use any lube you want to on it. I usually melt some lube (I used Crisco for year but recently got some bear oil/ beeswax lube i have been using) in a pan and dip a strip of patch material in it then lay it flat on a paper towel to dry.