anyone know how much is gained in velocity between a 8.5 inch gun and a 16 inch gun? Id like to build one as a handgun but I want it for deer hunting so velocity matters. I live in Michigan so have to follow a stupid law about max overall length a handgun can be so barrels longer then 8.5 are going to be questionable with an arm brace. So 10.5 barrels are kind of out of the running.