This gun will have a shroud, but not one that will affect the noise level of the gun, they are prohibited in Canada, unfortunately.... I will be using a 7/8" OD x 3/4" ID Carbon Fibre tube located on two 3/4" bosses, one on the front of the breech, and the other on the back of this modified Hatsan air stripper.... These strippers are available in .177, .22 and .25 cal (shown), having different inserts for the different bores.... The brass insert is adjustable fore-and-aft to adjust the air gap between it and the muzzle, which can have a dramatic effect on accuracy.... I will be making a .30 cal insert for the stripper on this gun....
The rear portion of the stripper was tapered, but I turned a parallel section with a 3/4" diameter up to where the stripper was 7/8" OD (where the shoulder is).... It will thread onto the end of the barrel on standard 1/2"-20 NF threads.... The shroud will mount between the bosses on the breech and stripper, and when the stripper is tightened up, the shouders will put the shroud in compression and the barrel under tension.... which should stiffen the barrel and raise it's resonant frequency.... In theory, this should reduce or eliminate the effect of barrel harmonics.... which can be quite a problem on long, thin barrels.... In addition, the woven finish of the CF tube should look pretty KEWL.... Once in place, all three tubes will be the same diameter, and also the same width as the breech....
Bob