does anyone have any tips on freeing up a froze axle nut on 300ex?

 

If its the skinny lock nut, you can split it with a chisel. You would need a new one after that but it would be off. You can also use that same chisel and hit on the point of the nut and usually get it to spin. A 2 pound hammer hitting a chisel can put alot of force on the nut.

 

Also may want to try heat - not a cutting torch but a propane and keep focused on the nut (watch for anything else that can burn -brake lines, plastic, etc...) Heat and the info in the last post together should work.
Good luck