Hmmm
My 4516-2 upper will work on my 4506 (early with square trigger guard) lower, but would not on another similar model 4506 I had. The 4566 upper I have will probably work on the 4516 I just purchased, tho I'm out of the country right now and can't try it.
Lew Horton produced a run of 4596's which were a 4516 slide on a 4506 frame. This is a really interesting combination.
I asked a big name gunsmith who is very familiar with the S&W autos once when I first discovered it would fit before I shot it if that would work, and he said: "can't see why not", but it doesn't seem all interchange with all...Mine does though, and I realy like it.
I know the DAO slides are usually longer; but the 4583 doesn't look it; hammers can be changed, but I'm really wondering about the internal mechanism in the receiver; does anybody KNOW they will NOT interchange?
Cheers, TF