It is the best of guns and the worst of guns. Combining the cheap stampings of a WalMart shovel with the simple reliability of a Lee Valley shovel, the Mossberg 590 feels like garbage yet works perfectly.
The 590 is one of several shotguns and variants based on Mossberg's 500. Some are more tacticool than others, some have a longer tube magazine, or ghost-ring sights; choose from pistol-grip, or adjustable stock, or fixed. Perhaps the most important variant is the 590A1, which has a thicker-walled barrel and some of the plastic replaced with metal, and was widely adopted by the US military and some law enforcement agencies. A heavier barrel is ideal if you think the shooter might try to do something stupid like use the shotgun to pry doors open, or as a cheater bar on a wrench to unstick a Humvee lug nut.
My pet Mossy is a 590 with 8+1 capacity, a heat shield, and fixed poly stock. Prior to writing this, I spent a couple of days just walking around the house with her; I couldn't go shooting, because it's minus thirty outside (Thanks, Notley!). Feeding a bunch of dummy cartridges, then shucking them out. I hadn't really noticed the poor build quality before; the heat shield is flexed at the spot welds, the plastic stock has rough flashing at the mould lines, every part of it was an exercise in mass production and bean-counter economy. If someone handed you one with the markings covered, you might assume it was garbage.
Let's take a moment here to calibrate your expectations, because some people are more sensitive to build quality than others. Are you the kind of person who chooses an axe based on it's colour? Would you buy a new crowbar because your old one is 'all beat up'? If you bought your MacBook because you love the way Apple machined the aluminum, you're not gonna like this shotgun
The Mossberg 590 ain't fancy. It's an old hammer, rattling around loose in the bottom of the tool box. It features no technology, any patents it may have had expired long ago. The steam-powered machine they use to stamp them out was built in England during the Great War.
So, if they're so ugly, what's the attraction? Just like any old hammer, the Mossberg 590 works every time. It feeds, fires, and extracts over and over and over. You can clean it with sweat and lubricate it with the blood of your foes (that's straight out of the users manual). Like that hammer, you never forget how to use it. When you're being chased by the range officer, the timer pushing you to panic, killing clay and steel enemies left and right, the 590 makes perfect sense. No excuses, and no BS about gas pressures or Frog Lube or ghost loads.
If you're new to 3Gun, or tactical shotgun use, the 590 is a calming presence, a Yoda on your back, urging you to run faster, jump higher, focus on the here and now. You don't have to think about it too much, it doesn't grab at your thumb during reloads, and with some practice you can pump almost as fast as a modern autoloader. The safety is right where it should be, under your thumb. The simplicity of it frees your mind to consider movement and transitions.
A modern autoloader, of course, shoots faster. It also loads faster, usually after some custom work on the loading gate. But unless you practice a lot, that autoloader can get you into trouble, causing you to fumble and curse when you should be moving and shooting. It's OK to come in last in a match, but it really hurts to come in last when you're rocking $2500 worth of Benelli. So take the old 590, and if you get your ass kicked you can always blame it on your cheap shotgun.
Which 500/590 should you buy? IMNSHO, the key features are personal fit and magazine size. Never buy a long gun without holding it, and measuring it against your body. Bring it up to your cheek a few times, see how easily your eye finds the sight. I prefer a single front bead on this gun, but you can get rear sights, ghost-rings, or perhaps install a small rail and mount an EOTech. That would be kinda like putting a biplane wing on a Civic, but...
Once you're sure it fits your face/shoulder/eye, get as much magazine as you can. These guns have been sold as 5+1, 7+1, and 8+1. There was a law-enforcement version that was 3+1 with a short barrel, but don't get that one unless your retirement plan is robbing liquor stores. In 3Gun, reloads are the downfall of many a competitor, so start with as many rounds as you can. There are also tube extensions available; I don't know how many rounds you could add before your pellets start sandblasting the end off the magazine. Nordic makes extension tubes up to +9, but your magazine would be sticking out two feet longer than your barrel. If you've tried any of these, comment or send me an email.
A last word, because I know that some people buy a shotgun for reasons other than sport. Is the Mossberg 590 suited to home defence? No. It's a shotgun, dumbass. Locks and gates and burglar alarms are suited to home defence. Moving to a safer neighbourhood is an excellent home defence. If you think someones gonna kick your door and rape your dog, spend your money on a better door. Shotguns are for sporting clays and range-day workouts.For those games, the Mossberg 590 is ideal.