A lot of assumptions there
One guy thinks it's a polygon barrel, and some others are jumping on the bandwagon and also think and agree that this must be a polygon barrel.
With all due respect, it is not
On the photo, the lands are clearly visible. Like I said before, the lands are rounded, which is pretty unique for a barrel, as most of them tend to have sharp lands.
A conventional barrel is more or less a cylindrical bore with protruding lands. (actually it is just the other way around, but you get the point
)
A polygonal barrel consists of 6 or more "flat edges with a twist" which go all the way through the barrel, hence the name "polygonal" (not a cylindrical bore)
As the lands in the HW barrel are clearly visible, it is absolutely not a polygonal barrel.
I just made some pictures, I hope they are clear enough, and that they will speak for their selves.
Example shows a piece of SPA M10 barrel, a piece of LW .22 poly barrel, and a HW100 barrel.
SPA M10 .22 barrel:
LW .22 polygonal barrel:
Poly, SPA and HW100 barrel side by side: