Cerveny 681

[Ulli]

I use a piece of newspaper or an electrician's tape around my mpc shank.
Ulli

[Mark Horne]

I never experienced a problem with the high C on mine - but I think the relatively large bore gives you less resistance (acoustic impedance) in the high range so there is a different feel. Plus the large receiver really works best with a euro shank so finding a familiar mouthpiece in the right size will make a difference.