Pretty sure the piston bearing bearing is OK Mick, as the piston now, with Weihrauch seal, pushes along quite easily. Less sure about the cocking arm, which is much harder to check as the stock needs to be replaced to give normal cocking conditions, and is then hard to check. I don't like this system, and I can see that there is some wear along the cocking slot, but if it is a problem why doesn't it show up with the Walther spring and seal in?