Looks a lot like a Mossberg 500 a very good friend of mine has, 12 ga, 20 inch barrel, but with a sling that comes across the belly and around the elbow of the triggering arm to help control and absorb the recoil. Works well with 00 buck and slugs. His preference is to alternate the two. I have fired it numerous times. A perp coming through the front door doesn’t have a chance.
Eighteen years ago I spent a weekend dove hunting with a borrowed 12 ga. I had a very painful shoulder after that weekend. But we went through several boxes of shells. It was definitely an over-dose of 12 ga. Mind you that was my first experience hunting, and before that I had never fired a 12 ga.