I recently purchased a mossberg 500 12 gauge shotgun. It's the silver combo pack and it comes with 2 barrels, one is a 28inch field barrel. The other is a 18.5 security barrel. I'm having a hard time finding out if the barrels can take chokes. The primary uses for the gun is gonna be turkey hunting and shooting clays. From what I found the 28 inch is a improvised fixed cylinder choke. Is that right and if so what does that mean? And if it's fixed is it gonna be practical for turkey and clay shooting? Like I said I'm a newbie but I'm trying to learn. Any info is appreciated.