The quality of the brassbarrels are fabulous. The muzzles are bored out and altough the muzzles are a bit underscale for this particular set they will undoubtably help to sell a models appearance.The shape is correct according to my references. The cladding has coolingribs. Near the muzzle the outer diameter of the barrels expands slightly as the original 365mm barrels did. 

Blastbags are nice and in most cases fits the barrels nicely. Sometimes need some help from a small round file, but it is a  2-second operation. Instructions are in japanese, but the simple drawings and the metric lengths that are given leave no doubt of what to do.

Brass barrels are not cheap to manufacture and this is reflected in the price. But for the price you get barrels that look more realistic. I bought this set with blastbags from Pacific Front Hobbies for $12.50.