Okay today I will tell you how to get xp in private match.

[spoil]You will need 2 people to start off.
One person creates a party match, then invites the other person. The other person then opens their playercard. Once the playercard is open, the host changes the lobby to combat training. The host may choose a map and gametype if they would like to. Once they have it the way they would like, they leave without party. For the person that is in their playercard, it will says game lobby closed. Ignore that and invite the person back. Once the person joins back the new host should hit a then b (A for Game lobby closed error, B to exit playercard)

It will say for the new host that they are in player match, but the old host that it is in combat training. The host should change the lobby to wager match, and then back to player match. The game will be ready to begin, you must have invite your friends now, you need 6 people to begin. No one will be able to join the game unless you invite them

You must do that each game, or it will go into some different game mode.

Note: Please do not put a video up on youtube, because it will be quicker for Treyarch to patch it.