Weihrauch HW100 T has become completely inaccurate

[jepho]

Welcome to the sometimes frustrating world of airguns.

As to barrel variability - yes this can occur, but generally such variability is not to the extreme you are experiencing.

You mention you have tried cleaning the barrel - how thorough was the cleaning?

Sometimes lead deposits can be stubborn to shift.

You also mentioned at some point that the rifle has been stored in a case, is there a possibility that some moisture could have been trapped in the barrel that has caused a patch of corrosion in the bore?

One other thought, IIRC the HW100 has a two piece action block - is this still firmly bolted together as if the scope is on two piece mounts it could theoretically cause some movement if the two halves are loose.

Thanks for this response. The cleaning was carried out with Napier and patches on a pull-through. I guess the point about corrosion in the barrel through moisture is a possibility. The house is kept at an even temperature and does not suffer during the cold weather. Moving from well heated to a cold environment could potentially provoke condensation and that may provide enough moisture to corrode the barrel. When I inspected the barrel from both ends against a strong light source, I could see no variation in lands or rifling grooves. Good point about the action block. It is very firmly bolted together.