Golly that's bad, hard to believe that's even possible.
Depending on if the barrel is tapered or not, that would change the manufacturing process, but I suspect they are using DOM aluminum, or Drawn Over Mandrel for those who don't know what that is.
Basically you have a steel rod that goes in a tube, and you whack it from the outside with a special machine to get a decent tube that doesn't have a seam. Can't say how the aluminum company messed this up(the stuff is very specialized and IDK if ANY airsoft manufacturers make their own material), but it is rather impressive to say the least. This is an issue with rifle barrels when mounting a suppressor or a specialized muzzle device where your bullet has to make it through a similar diameter hole, as many rifle barrels have a bore that can be perfectly straight, but not parallel with the outer wall. I feel that this is seen more in tapered barrels for some reason, just a thought so it may be wrong, but I feel that straight barrels are easier to make.
Could also be a case of warping, where the grain structure in one side pulls more than the other while it is machined, and it creates a warp that if corrected by cutting down the high spots, will result in a bore that isn't centered. Could be heat treating based warps as well, but cold worked aluminums are usually not heat treated as they have already been naturally work hardened.
Anyways, why not make a Blind Sniper carbon fiber one?
I'm sure that it couldn't be astronomically harder than a VSR barrel lol.
