I was wondering how do you access the armory for battling? Also if you put a weapon into the armory can you remove it? Thanks for any and all help!

The armory is one of the links in the coliseum's navigation. Yes, you can remove weapons from your armory.

http://subeta.net/games/battle/armory.php

you can remove weapons but they lose any modifications when removed

too slow with my answer

Thank you so much! I don't battle very often and wasn't sure where to find the armory. Thanks Really appreciate both of your help :)