Ok, this one really makes me feel dumb for asking but here goes... When looking at scope bases I'll see references to 8-40 screws. I'm assuming this is just another size of screws but is it somehow better?
For years the standard has been 6-48 screws when scopes averaged about 12-20oz. 8-40's are probably 50% beefier. With the advent of much heavier scopes this size is probably a good idea. Of course a better idea is the base being part of the receiver but then your stuck with the MOA angle or lack of on the base and the additional expense of making the one-piece receiver.
Engineers will tell you that loading a screw in shear like that is a bad idea for a lot of reasons. Of course, people have discovered over the years that covering up a bad idea with bigger parts is a recipe for success.
Now that I've got the snark out of me, they're just bigger screws, and about right for the application.