I recently discovered that I can mod Red Dead Redemption Multiplayer.
Now, If you'd like to have Level 50 (Legend), All Golden Guns, War Horse, All titles : Including DLC, ALL characters & All mounts.
You must have the following:
1) A Brain.
2) A USB/Flashdrive/Junk drive.
3) A computer (Obviously)
4) MODIO!

Now that we have all that settled, You must now do the following:
1) Connect the USB to your Xbox 360.
2) Go to System Settings>Storage>Hard Drive>Games&Apps>Red Dead Redemption.
3) Now that you are at your game in your HDD, Look for the RDR Multiplayer.
4) Click it>Copy & move it to your USB.
Once you have done that, Remove your USB and connect it to your computer.
5) This is when modio comes in, open up modio & click OPEN FROM DEVICE
6) Select the profile>Game>Then click your RDR2MPSAVE.SAV.
7) Now that the file is open, DRAG it to your desktop.
8) LAST STEP , GO TO YOUR EMAIL!
MOST IMPORTANT
Send your multiplayer gamesave to this email:
[email protected]
Now that we are done with the difficult stuff, Wait about 10-15 minutes.
You will receive an email from ME .

Now, Connect the USB back to your PC & move the gamesave from the email to your desktop. Once done, Open modio again & This time click Explore My Device
Now, Once you see your OLD RDR2MPSAVE.SAV Erase it and right click & select add file , click desktop and scroll till you see the gamesave. Once that is done, Close everything out.
Reconnect to your XBOX 360 & Start up multiplayer, It'll say something like this " There a multiple multiplayer gamesaves, select one" then you click ok.
Load the USB and HAPPY MODDING!

IF YOU DO NOT HAVE MODIO GO DOWNLOAD IT !
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IF there are any questions, Please feel free to message me for help!