I found this by MYSELF! I released this first.

YOU CAN EITHER FOLLOW THE TUTORIAL, OR IF YOU DON'T WANT TO, THANK THE TOPIC AND SEND ME A MESSAGE OF YOUR TTG USERNAME ON XBOX. I WILL CHECK, IF YOU HAVE THANKED, I WILL SEND YOU A FRIEND REQUEST, THEN DOWNLOAD THE CLIP CALLED '6 Man Collateral''. MY GAMERTAG IS: 'Wazzle HD v2'


Tutorial.

1) Go into options and make sure game recording is on.
2) Go into a private match and make a class with a L11 (Sniper) with overkill, then make your secondary an assualt rifle with grenade launcher.
3) Start the private match on any map.
4) Pull out your secondary and press Y and left on the Dpad at the same time, if done correctly, you should lift your sniper up. (See: Forums/t=2555254/modern-warfare-3...orial.html for more)
5) End the game and go into 'Vault' on the multiplayer menu.
6) Start to watch your clip, when it gets to the bit where you do the glitch, press 'X' and record it for a few seconds.
7) Then stop recording and end the clip (Press start and it's at the bottom)
8 ) It should ask you to save some clips, click 'Yes' and save them.
9) Upload that clip to your file share and name it something like '6 Man collateral!' and get your victim to watch it!!

Video: Sorry about the quality, it's my iPod...

I hope I helped!!

Please thank the topic!!