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.
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.