The The Butcher's AK/CAR Mod Pack Add-on for PAYDAY 2 has 8 achievements.
In the Art Gallery job, complete the heist in stealth within 4 minutes with each crew member wearing the Improved Combined Tactical Vest and no Armor Bag deployable equipped. Unlocks the "Classic Stock" for the AK weapon family, "2 Piece Stock" for the AK and CAR weapon families, "Pachy" mask, "Fossil" material and "Prehistoric Predator" pattern.