Probably a GSG 1911 22. It comes with a threaded barrel, nice trigger, looks good, quiet, and inexpensive to buy and run ammo through. You should check out sturmgewehre's review on youtube. He has it set up with an inexpensive supressor too so you can see what thats like.
Both come to mind pretty quickly. I'm assuming you would want something full size and high capacity for a range gun. My only other choice would be a SA XDM 9 with a bar-sto threaded barrel.