They are expensive
Thanks but believe it or not it's actually a 500 with ghost ring sight and heat shield. Sportsman Outdoors Superstore had it on sale for $329. I must've gotten one of last ones because soon after I clicked it was out of stock. It has a bright red front sight that makes it easier to acquire target.Nice buy. I got that same 590A1. Top quality shotgun. And that's a decent price on those rounds at a lgs. I see them for $5 for a five round box at mine.
That is well proven design that started out as Remington Model 31. This is improved version with dual action rails and bolt that locks into barrel extension. The Remington 31 produced with "Dural frame" (aluminum alloy) ca. 1949 had barrel that locked into receiver via threaded steel insert.