I'm active Army, and the good ol "Big Army" has a pretty clear "no solvents" policy most of the time, except for like solvent tanks. I see Soldiers using Carb Cleaner on their M4's and tell them no no. I do use Hoppes on my personal firearms and on my issue M4 as I make sure to use very little and don't leave it on the firearm. I instruct my Soldiers to do the same and they love the big ol bottle of Hoppes that Sarnt V. Keeps by his desk.
-SGt John V.