The rifle in Breakout is NOT an M14, it is a modern copy by the company Ruger. One can tell by the synthetic furtniture and the smaller size. The rifle in-game is a Ruger Mini-14.
 Kane & Lynch: Deadmen
The Mini-14 is only seen in the Breakout chapter. You will wish it was elsewhere due to its incredible stopping power and accuracy. it is a recommended weapon for the chapter.
As stated above the weaopn is only in Breakout and not available in Fragile Alliance.