Available from:
http://muzzlemack.com/default.aspx
10.5"custom 2 Step Crowned Extended Target barrels in .177 & .22 Cal
for the Webley Alecto and Zoraki HP-01 Pistols
Extended section is 7/16" OD and will fit Crossman 22xx barrel goodies
$40 + Shipping
Note: as with all customisation especially with Crosmans it is advisable to use a chronograph to ensure you pistol is still legal. Use the services of a gunsmith unless you have the skills required to cut down the barrel and recrown.
Then you can have fun adding silencers, muzzlebreaks, etc
Cheers
Ian