FX Dreamline barrel liner deposits

Is it causing accuracy loss? Typically barrels have to lead in a bit to achieve peak accuracy after cleaning anyway, so if it isn't bothering anything, I'd leave it be. If it is, I might pull the liner and use a very VERY mild bore solvent such as Hoppes. 

The other thing I'd mention is that looking down a barrel produces some very unusual optical artifacts, so you might want to scope the bore to see whats what before going deep on cleaning. This is also why I started with the question of accuracy, because there may be nothing out of place at all. *shrug*



I hope that helps mate. :)