Put some imperial wax on the mandrill and it should work fine. I also polish the mandrill with Flitz and 0000 steel wool to slick it up. You can get different sized or custom mandrills too if still difficult. Annealing the case can help too if the case has had a couple of firings already.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli