Bone stock Remington 870 Express Magnum 12ga with 20" smoothbore slug barrel loaded with Remington 3" #4 Buck. I picked the gun up for $150 from a coworker and I've been very pleased with it. I did try a 3-shot mag extension, but when fully loaded it made the gun, IMHO, too heavy and poorly balanced. I also keep a converted Saiga 223 loaded with 20 rounds of Winchester 45grn JHP and a S&W 629 loaded with Speer 240grn Gold Dots handy. If all else fails, I also have a H&R Pardner 10ga in the closet with 5 rounds of Remington BB shot in a butt cuff.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar