Considering what you already have,I think I would go for a nice used AR, and a used pump shotgun, you should be able to get both used right here for $1000
I have a Sig 229 along with a few other hand guns. Its nice but if I were you I would save another $200 includes tax and buy a Springfield EMP 40. I bought one and it is now my daily carry.
You have a go-to handgun and a go-to rifle and a plinker. Assuming you are happy with these, what else do you need?
A semi-auto or pump gun for busting clays?
Home defence style shotgun, also useful for busting clays?
A nice revolver? plinker, carry, or cannon?
A 1911?
An accurate rifle? probably a mid-bore bolt action?
Save a few hundred more and get a Springfield M1A. That will fit nicely into your collection and when you go to the range it's fun to hear everyone go "WOW" and come over to check it out!