The Mossberg 930 is a gas operated semi automatic (autoloading) shotgun.  My review of this shotgun is below:

Basics
The Mossberg 930 is gas operated, which means that some of the hot gases from the burning gun powder are used to push a piston that operates the action, ejecting the spent hull and chambering a fresh shell.  This gas action reduces the recoil felt by the shooter, making this shotgun a good choice for the recoil sensitive.  In my (purely subjective) tests, the recoil from the Mossberg 930 is a bit harder than the Remington 11-87 (and Beretta’s gas operated shotguns recoil softer than either the Mossberg or Remington offerings).  Like other Mossberg shotguns, such as the Mossberg 500, this shotgun has an ambidextrous safety that is located on the rear of the receiver.  The Mossberg 930 (and the Mossberg 935, which takes 3.5″ Magnum shells) come in a variety of models suitable for home defense, hunting, trapshooting, etc.  The 930 is available in the usual gauges, but I’m only concerned with 12 gauge.  One thing I’ve noticed is that the Mossberg 930 seems to eject spent shells a few yards further than my Remington 11-87.  This doesn’t really matter to me, as I use a shell catcher, but I found it to be interesting.

Build Quality
The Mossberg 930 is well known for its low price, which is achieved without sacrificing quality or safety.  On thing that I dislike is the aluminum receiver, as I prefer steel, however I can’t honestly say that the choice of metals has made any noticeable difference for me. I also wish that the safety were made of metal, rather than plastic, however I have not experienced any durability issues with the safety.  Given the fact that one could practically buy two of the Mossberg 930 for the price of a single Remington 11-87, the aluminum receiver and plastic safety seem quite forgivable.

Reliability
I have had no issues with the Mossberg 930 failing to feed, failing to fire, or otherwise malfunctioning.  That said, keeping any gas operated shotgun well cleaned is essential to reliable operation.  Since I keep my shotguns well cleaned and lubricated, I don’t anticipate problems.  At the same time, prefer pump action shotguns for home defense, as the pump action is inherently more reliable.

Accessories
The Mossberg 930 is quite popular, due in no small part to its low price. There is a wide variety of accessories available for the 930, in stores and online. Barrels can be purchased for just about every shotgunning discipline imaginable, including trapshooting, hunting, and home defense. Scopes, laser sights, ghost ring sights, pistol grips, stocks, and more are available too. There is even the 930 SPX model, which comes with pretty much all the tactical accessories one would want, right from the factory.

Conclusion
Those looking for an inexpensive yet good quality semi auto shotgun may want to consider the Mossberg 930.  I prefer my Remington 11-87, however the Mossberg 930′s price just can’t be beaten.