bought a .177 barrel for my .22 tempest from chambers
It took 10 minutes to fit and pushes pellets out at 440 ft/sec
An easy conversion and the barrel quality/blueing was on par with the original

On the other hand I bought a .177 barrel from J Knibbs recently for a early Premier and it took 2 hours plus quite a bit of filing to get it to fit and work correctlyAs received it would not even close nor would a pellet exit the barrel - very disappointing quality and obviously no receipt inspection carried out by J K