I eventually got the compartment open. It took a pair of vice grips, channel locks, two people, a quarter and dings on the knob. I had to hold the knob with channel locks and hold a quarter with vice grips and have one person hold the channel locks and one person turn the cover. To think that a company thinks that it is alright to tighten this compartment so much that you can't get it open without using the strength of two men and tools is just ridiculous. I'm going to call Millet tomorrow and talk to them about this issue and hopefully they will send me a new battery compartment cover because mine has scuff marks and dings all in it from struggling. Also on a side note, the windage adjustment knob cover was bent when I received the scope. Millet should be using higher quality materials than what this scope is made of. Disappointed in this scope to say the least.