I have not noticed a difference in barrel fouling, but the suppressors do end up making a "dirtier" gun. In a bolt gun, this is hardly noticeable. In a gas gun however, even on my piston uppers, the back pressure leads to very dirty chambers and FCG. Non-piston AR's get downright FILTHY within 20 shots.
It is good policy to remove the suppressors after shooting, (while they are still warm) to reduce the amount of moisture they harbor. If left on the gun it can lead to a pretty nasty barrel after a while. For this reason I'm a big fan of QD mounts, namely the "ratchet" style designs. My favorite is the YHM. It is quite easy to index and get the can back to the same spot each time.
I will notice the rifle will shot slightly worse when I remove the suppressor. This is due to the fact the load is developed with the suppressor on. Hanging 2lbs off the end of the barrel will definitely change the harmonics slightly. Thusly, I like thick short barrels if I'm working with a platform that will be primarily suppressed.
As others mentioned, removing the suppressor also results in a POI shift. On all my suppressed guns this is repeatable, and easily compensated for.
It is good policy to remove the suppressors after shooting, (while they are still warm) to reduce the amount of moisture they harbor. If left on the gun it can lead to a pretty nasty barrel after a while. For this reason I'm a big fan of QD mounts, namely the "ratchet" style designs. My favorite is the YHM. It is quite easy to index and get the can back to the same spot each time.
I will notice the rifle will shot slightly worse when I remove the suppressor. This is due to the fact the load is developed with the suppressor on. Hanging 2lbs off the end of the barrel will definitely change the harmonics slightly. Thusly, I like thick short barrels if I'm working with a platform that will be primarily suppressed.
As others mentioned, removing the suppressor also results in a POI shift. On all my suppressed guns this is repeatable, and easily compensated for.