With regards to Barrel cleaning, has anyone else noticed that their EV2 needs its barrel cleaning after around 500 shots or so as it starts to go off.

I ask as this is what i'm finding.

Would it perhaps be better if i polished the barrel (internally of course).
Has anyone else done this and what were their results like afterwards?

And finally, what is the best way to polish a barrel up?

Many thanks,
Steve Ed