Depends on the gun. If it was a 870 wingmaster for a decent price I would consider it. Possibly even an 1100 by remington.

For an everything gun you are pretty limited on your options unless you want to spend a lot of money.

Sorry, you said rifled slugs, you could do that with a regular barrel so you wouldn't have to buy another one. You would be stuck with fixed choke though, verses a newer gun that would have screw in chokes. The choke you would use with slugs would not be the choke you would want for birds or turkey.

Paul