The caldwell does not need any other ### bolts or screws, takes a few minutes to install and remove and is very solid.
It's got a rubber gasket that compresses and provides friction between the adapter and the stock and there is a cross bolt that goes through the sling stud hole and locks one half of the system while the other half is tightened on with two machine screws that push against the section that is locked into the stud and tightens things nice and snug.
I prefer the ### bolts.