Yes, you chose right and no, you didn't screw up. I own 2 Winchester Defenders. I love them both. They are FAST!!! The action is the fastest there is because the bolt opens a split second after a shot is fired. That leads to a faster cycling action for the second shot. It practiclly pumps its own self! And the action is smooth!!! You know, FN is now selling the Defender as the FN Police & Military Shotgun. FN is not noted for supporting junk, as witnessed by FN Browning Hi-Powers, FALs, the M-249 SAW, and other quality firearms. Like the man said, you already have the max mag capacity for an 18 inch barrel. You don't have to dicker around with the gun. If yours doesn't have the Tru-Glo sight, you can order it from Winchester. It snaps right on over the brass bead.
When I bought my first Defender, I was surprised at what a great shotgun it was. That's why I got me a second one. I have a wood stocked Defender and the synthetic stocked one. Kind of like having two decks of cards, you know? I enjoy my Defenders tremendously and they are a screaming deal for the price. They're easy to disassemble and clean. And they will last for you.
Enjoy that shotgun. Get you plenty of shells and practice with it and you'll see that you made the right choice.
