How can I stop primer from eating my roller handles?
A better roller frame may actually be the right solution. I used this roller to paint most of my house after giving up on the cheap ones. It does a pretty good job of sealing the ends so that paint doesn't get inside to the rotating components. It's also got bearings to help it roll smoothly. 


Unfortunately, I've used it only with Behr interior eggshell paint, so I can't tell you how it will do with primer.

EDIT: Mike B. reports good results with primer for the same roller.