I really like my HW45 - bought it as .177 second-hand, but was disappointed to find that someone had ruined one of the barrel screws by shearing the head off (having described it in his post as being in "excellent condition"!). I persuaded a friend who is a supervisor in an engineering works to get the stub of the screw removed for me and managed to source replacement screws. I then bought a .22 barrel and can now swap between the two. Result!
S200 .177 with 10-shot conversion and Simmons 44 Mag 3.8-12x44mm Diamond WA, S510 .177 with Hawke Vantage IR 3-9x40mm (& PARD NV007A), TX200HC .22 with Nikko Sterling Panamax 3-9x40 AO IR, Weihrauch HW45 .177 with Dowling & Rowe red dot