User blog comment:Argorrath/Treyarch confirms that there will be no more gun DLC/@comment-3463306-20130410150556/@comment-68.199.100.76-20130413201024

Peacekeeper fires the same round as the P90 and PDW (which is overpowered even after the nerf(s)). Which has better ballistics than the current 5.56 round.