This is how I rank up fast using a Riot Sheild and Cage Match.
You Get 10,000 to 13,500 per match at 10 minutes per match. So, do the math. approx. 1,250 XP per minute. Not bad.
This is how to set it up.
You: Riot Sheild and Tactical Insertion.
Friend: Hardline and Sentry Gun.
1. Get into Cage Match.
2. Have your friend get a 4 Killstreak to get his Sentry Gun.
3. Now have your friend do the Unlimited Care Package Glitch. (Over and Over)
4. Now just have him keep placing them.
5. Stand there and take bullets until it stops giving maximum points. (The more Sentry Guns that are out there the faster you'll acheieve maximum points thus, more points in the end. You acheieve Max points when the score starts decreasing.)
6. Once it stops giving maximum points back off and wait 15-17 seconds for the score to regenerate.
NOTE: To get MAXIMUM points everytime your friend puts out the Third or Fourth Sentry Gun Destroy the one that has been out the longest to get 200 points everytime.
Just keep repeating the process.
Please Thank or +Rep if this was helpful and I'll be sure to return the favor.