RE: What Gun?
Shoot with the gun that feels best to you. Weight, fit and your swing are more important than the make of the gun. I' ve seen guys drop some serious $$ for skeet & trap guns with no improvement in their scores.
I shoot a Win 1300, but that' s me. If you' re most comfortable with a Rem 11-87 follow the advice and have it checked out. Hopefully, all it needs is a good breakdown & cleaning session.
Some other popular semi-auto scatterguns:
a. Benelli has one, 391 I think.
b. Browning Gold. (There' s the A5 too, discontinued)
c. Winchester SX2