List of M-designations?

[sic1701]

OK, I figured I'd run this one by the Brain Trust, here...is there a comprehensive list somewhere online, or can someone here provide a link or PDF or Excel, of all of the M-designations (and I'm sure I'm not using the correct terminology here) used by the U.S. military during the 80s to current?

I know M4 is the newer carbine, of course there's the ubitiquous M16 and M203, but what are the designations for, say, the 203's various and sundry grenades?

And while we're on the subject, why don't some weapons used by the Army go by M-designations, such as the Mark-19 tripod-mounted and vehicle-mounted automatic grenade launcher? Or the Javelin and Predator anti-armor weapons? Or the Mark-23 SOCOM "Supergun"?

Also, I know many things have the same designation, but are seldom in use at the same time...the M1 Abrahms tank clearly was not in use at the time that the M1 rifle was. And yet, the M2 .50 caliber machine gun is in use, and can be mounted upon, the M2 Bradley APC.

For my own campaign, I designated the Mark-19 the M96. For what it's worth.