This info is second-hand, just so you know...
I recently did some (more) training with a few swat guys as my NCOIC is a swat leader and makes the calls on equipment issue and allowances. He acquired Noveske KX3s for his guys who run SBRs. His reasoning behind the KX3 was that it increases back-pressure to help an SBR run more reliably, and the shape of it sends the muzzle blast downrange and not to the side where a fellow officer might be standing. At one time he forbid one of his guys from running a comp that generated too much sideways/rear muzzle blast and noise that would have been a liability/distraction for other officers in confined spaces.
I realize you stated "daily carbines," but for these officers their SBRs are their daily carbines, and you might also have a few guys running shorties. Hope this helps.