The SPAS-12 (Sporting Purpose Automatic Shotgun-12 gauge) is a dual-mode (both pump-action and semi-automatic) shotgun manufactured by Luigi Franchi SpA. The SPAS-12 is a predecessor to the SPAS-15 variant.
Like the M1014, the SPAS-12 can be a vicious shotgun at close range thanks to its semi-automatic nature. It will kill if shot at point blank, or two to three shots to the chest, dependant on the range shot.
Italics are generic gadgets. See Operators for their unique abilities and gadgets.
Tom Clancy's Rainbow Six: Rogue Spear
The SPAS-12 in-game is incorrectly shown as being a select-fire semi-auto/full-auto shotgun when it should have a convertible pump-action/semi-auto fire.
The SPAS-12's tube magazine's capacity is also incorrect with 9 rounds when the real capacity should be 8 rounds. The only way 9 rounds would be correct was if the game had a 8(+1 in the chamber) capacity.
Tom Clancy's Rainbow Six: Vegas 1 and 2
The SPAS-12 is limited to firing only in pump action.
One interesting thing to note is that when a player is in the weapon selection screen, the stock is shown folded, but the stock is seen unfolded in-game.