Have used DuraCoat on a barrel and have Rattle canned a barrel ( whole gun actually).
Dura coats more durable/ permeant but they both wear.
If I was going to Rattle can I'd use Rust-Oleum type spray paint ( thick textured type). Have used it to good effect camouflaging afew guns and it seems to stay on alot better when gun cleaners get on it as oppsed to plain black spray paint that will get sticky and goop off.