Just received my "sub" from m&p today...great so far, however, I realized I haven't the foggiest idea as to how to change the carto when the time comes. I've checked youtube & couldn't come up w/anything except one that showed attaching the end of a new carto to the battery end of the one being replaced & pushing it up. I really hate to ruin my new baby, therefore I realllly need help on this....ANYONE PLEEEZ!
