When this site was originally created it primarily attracted current owners of the SPAS12 shotgun who needed parts, a manual, etc. Now that more people are just happening across it, I thought some sort of general introduction would be helpful.
The exact name on the receiver is S.P.A.S. 12, which is short for Sporting Purpose Automatic Shotgun in the USA. For details on why, or what SPAS may also mean see here. (That is the cover of the original, color user's manual above. Don't be wasting your time writing me it means something else).
For you game players out there who happened to stumble across this site: Yes, the SPAS12 is a real 12 Ga. shotgun. It is semi-auto -- no, there is no full-auto version of it. While it is certainly possible for one to be converted to full-auto, it would be of little value and fairly illegal. There is no point; you can fire a semi-auto as fast as you are ready for the next shot. No, I don't think it would be great to rechamber it for 3" or 3.5" shells. Again, in the real world, the kick of a 2.75" shell is painful enough. Most police (and I) tend to use reduced load "tactical" rounds to ease the pain and lessen the chance of penetrating walls, etc. (Just amazing how many little boys who have never held a real shotgun write and write me how I am wrong about them)
Dual Mode Shotguns
Police departments and the military typically are forced to use pump-action shotguns because they must sometimes shoot rounds (such as a beanbag or tear gas round) that do not develop sufficient gas pressure to cycle a semi-auto shotgun. Many just use pumps because they don't trust the reliability of a semi-auto shotgun.
Dual mode shotguns such as the SPAS12 give the best of both types - they can be operated both as a pump-action style shotgun and as a semi-auto shotgun. They can rapidly fire full power loads such as buckshot set on semi-auto, and can be switched to pump to handle low power rounds -- or if auto functioning fails to function properly. There are some trade-offs.
Civilian vs. Police vs. Combat Shotguns
We've all seen Civilian or Hunting shotguns. Long barrels, small magazine capacities, often beautiful wood stocks. I won't go into any more detail.
Police shotguns are enhanced for the specific needs of the Police. They hold more rounds because the battle with three bank robbers takes more rounds than killing a deer. They may have pistol grips for one-handed use, folding stocks for easier storage. The barrel may have a minimal heat shield since it gets kind of hot after 6 or 8 rounds. The barrel is very short (14 - 22") as use at much closer range doesn't require as tight a pattern as a hunter needs. The short barrel makes use easier in tight quarters. Sight systems optimized for police use, such as Ghost Ring sites, are used. Synthetic stocks are often used for weight reduction. They often have a special metal finish to survive humid automobile storage and to minimize reflections off the gun during use. Other than that, most are just like their Hunting brother models.
Police shotguns spend most of their life in a rack in the trunk or passenger compartment of a police car. They are pulled out now and then, some may not ever be fired in action. Except for the most unusual of situations, the magazine is rarely emptied, more rarely reloaded. This is why the barrel heat shield tends to be optional. Pump-actions tend to be used exclusively, Dual Mode shotguns haven't caught on yet.
Typical Police shotguns would be the "Police", "Defender", etc. models of the Remington 870, Winchester 1200/1300, Mossberg 500, and the Franchi SAS12. (SAS, not SPAS). The Benelli M1 Entry Gun and M3 (M3 is Dual Mode like the SPAS), and would also fit into this Police category.
Military shotguns are designed or adapted for use in the battlefield. They have the same basic needs as the Police, plus they are carried for miles, dragged around everywhere, hid with their user in ditches. If a battle takes place they may fire several dozen rounds, may be shot till their barrels start to glow. A good functional barrel heatshield is needed, not some simple after-thought clamped on deal that gets hot after 16 rounds. Military finishes like Parkerizing or phosphating are used vs. the high-tech black finishes on Police guns, bluing on Hunting guns.
The SPAS12 is an example of a Military shotgun. It has a heavy heat guard over areas of the gun likely to get hot during prolonged operation. It has a latch on the magazine loading door that keeps out rocks and such when crawling along in a trench with it. It has a "hook" on the end of the folding-stock that acts as a carry handle and a shooting support. It has a number of other special features that adapt it specifically for police and military use, such as a magazine cut-off button that stops feeding of shells from the magazine so that the slide may be opened without a new round coming out of the magazine. This could allow a special round to be manually inserted.
So Does That Make The SPAS12 The Best?
The above listed features make the gun well suited for military use, but can become detractions for civilian use. The heat shielding makes the gun very heavy. The latch on the magazine loading door is just thought of as just a hassle by many civilian users. It takes considerable training and drilling to learn how to operate. Try to keep in mind the specific market and role the gun was designed for.
It might not be what you really want, it is not the right gun for every person and every need. If it does fit your needs, or you just think it looks cool, buy one by all means. But if you just want a shotgun around the house for prowlers, I'd strongly recommend you use a Winchester 1300 Defender or Police pump (I do).
What Else Is A SPAS12?
The folding stock version of the gun is very, very, very photogenic. Movie directors just love to have one in just about any movie with guns in it. Take a look at the list we have complied so far. The folding stock is always the most desirable amongst collectors, but the fixed synthetic stock version is actually most comfortable to shoot - the metal stock is much more painful to shoot. And while the SPAS12 is one of the more comfortable guns to try to shoot with the stock folded up holding the pistol grip (due to its weight and semi-auto action), you'll likely try shooting it that way only once. The purpose of the folding stock is really just to allow storage in a smaller location - the stock just about must be unfolded before use.
I mentioned "collectors" in the previous paragraph because no more of these guns may be legally imported into the USA. The Franchi production stopped around 2000. All the ones that will ever be in the USA are here now. Thus, the rarity and the "collector value" determines what these guns are worth. The gun is treated as an ordinary shotgun in most normal states (i.e. not Kalifornia).
There are other members of the Franchi SPAS family you can see on my SPAS12 NOT page. While the SPAS12 was just an existing shotgun receiver with a bunch of stuff added, the SPAS15 was a new top-to-bottom design which overcomes some of the criticisms of the SPAS12. Unfortunately, only about 180 were imported before they too were banned. The tend to bring between $4,000 and $5,000 USD these days and are almost never used, just traded like gold coins.