I have a Posi front mount that the plunger works fine when unmounted but when I tighten down the mount screw the plunger binds up. I am wondering if anyone has fixed this without taking the whole scope apart to have the mount loose to clean up the plunger bore.

Thank you,
Charles

Are you talking about the plunger that rides on the Pope rib on the front mount. If so you can unscrew the slotted top cap off and under it is just a spring and the plunger itself to take a look at. Once you have it out see how easy or hard it slides on the rib just by hand. I have seen a few with sharp edges on the sides of the slot that want to dig into the sides of the rib instead of wanting to slide. And if so a stone can easily cure that problem. Or it could just possibly be that the plunger and the bore it rides in needs to be cleaned. 
You would probably want to do this with the scope still mounted on the rifle so you see why it is binding up. Loosen the mount if need be to get the plunger out and then re-tighten it so you know where and why the plunger is getting stuck.

AND be warned, 
A. Be careful the spring does not fly to areas unknown
as you unscrew the retaining cap
B. You need to have care and patience to screw the cap back on over the spring w/o cross threading it..
beltfed/arnie