The Mossberg 590 is the dedicated defensive variant of Mossberg's 500-series pump platform. It runs an 18.5-inch barrel and holds 6 shells in the tube plus one in the chamber, giving you a 7-shot configuration with 2-3/4 inch loads at 38.63 inches overall and 100.8 oz (6.3 lbs). The aluminum alloy receiver is anodized — the same finish as the base 500 — and it skips the heavy-walled barrel and parkerizing that push the mil-spec 590A1 up to 116 oz.

Mechanically the 590 differs from the 500 mainly in the magazine tube: the 590 uses an open-end tube with a screw-on cap that lets the barrel mount further forward, which is what gives it the extra round of capacity. Compared to the Remington 870 Express, the 590 saves about 19 oz at 100.8 oz versus the 870's 120 oz, and the top tang safety is ambidextrous from the factory — the 870's cross-bolt safety is a common left-handed swap candidate. Reviewers consistently note the lighter weight is easier on the support arm during extended drills, though the trade-off is less mass to dampen recoil from full-power 3-inch loads.

One practical detail worth knowing before you buy: the receiver is drilled and tapped from the factory, which means a ghost ring sight, optic rail, or side-saddle mount goes on with the existing screws — no gunsmith required. That's the cheapest path to a slug-capable upgrade if you want one. The 590A1 ships with ghost rings standard if you'd rather skip the aftermarket math.