Get your self a lapco big shot barrel. Comes in stainless or aluminium. It has a fairly large bore so should be able to handle ****e site paint. It has porting just at the end of the barrel so you get good gas efficiency and dispersion. And it is an extremely well made barrle which is still quite cheap ( $50ish for the aluminium, $75ish for the stainless) Stainless is 11.5" long and the alu comes in 11.5" or 13.5"