This item is a photo-etched detail parts set for detailing AFV kits.
Voyager Model of China is a manufacturer of some of the best photo-etched metal and resin detail parts in the industry! They are, as it says right on the box, "The Best Upgrade Solution!"
This is a set of photo-etched metal, resin and other detail parts as shown here for the application described in the title. Metal gun barrel not included in this set.