What correction were you using (attrition or nick). We have a friend who has had to very vocal chessies. The noise came through high prey drive and being controlled (not getting the mark they wanted). The more the pressure the higher the noise.
Do you do a "blind drill?. I have found that this drill really cements the concept of pulling off a mark to run blind, poison birds and getting passed a gunner in the field. M is due for a refresher on it.