Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!
Microsoft MSN, Live, Hotmail, Outlook email users may not be receiving emails. We are working to resolve this issue. Please add support@steelsoldiers.com to your trusted contacts.
Search for a thread by 'westfolk' that was titled "for those that want to know what 'M' is".
In there is a list of all the M numbered vehicles and what they are.
You should find your answer there..