Here is the full list of all 12 Special Forces: Team X achievements.
Reach Operator Rank 40
Win a match in all Game Types
Kill 25 enemies with an attack dog
Reach Operator Rank 20
Kill an enemy with his own mine
Achieve a teamplay multiplier of 4x or better
Reach Operator Rank 2
Complete one Player Mission
Kill four enemies with a single explosive
Complete all Player Missions
Kill 20 enemies in a match
Execute 25 enemies