Are you asking about inner or outer barrels? Inners are always metal and can be made of brass. Most outers are metal but NEVER made out of brass. Good rule of thumb is if they have a threaded flash hider connector, it's probably a metal outer barrel. Not sure why your asking either but if it's due to strength, keep in mind metal used in Chinese guns isn't the greatest in quality.
It would help if you specified which 1 too, but doesn't really matter on Echo 1's . They are all relabelled Chinese brands anyway. If you do a little more research on your end you can figure out the Chinese brand and save yourself $30-$50 bux, unless that 30 day warranty gives you a warm and fuzzy.