My pistol is in pretty fine grained stuff, but I have a DSB and almost my entire tank is rock with only a tiny bit of sand around the edges and a small sand island in the corner. The pistol is def. making a big pile of sand mess as he digs out under the rocks, but he and his goby buddy seem content with using the rock in conjunction with the sand as opposed to making roundish hole/tunnel directly into the sand.
If you dont have a deep sand bed then you really should add some rougher sand and tiny rubble likes stuff fo them to use.