Plain military holsters used "bridal leather", which comes out to about 7-8 oz. Some civilian holsters of the later 19th - 20th Century period, with a lot of carving, probably 8-9 oz. Much earlier, cheap holsters might use 6-7 oz. I tend to use 8-9 for most civilian holsters, and 7-8 oz for military rigs. It depends on the particular pattern designation.