Here's a comprehensive list of where you can find ammo today

The $64K question. For the younger members that's a reference your too young to know.
TSgt David L., SPC Randy Zimmerman,
SGT James Murphy, CPT Jack Durish,
PO3 Bob McCord, SSG Gordon Holmes,
COL Mikel J. Burroughs, SGT Robert Pryor,
SPC Gary Welch, SGT Mark Anderson,
CPL Douglas Chrysler, Maj Marty Hogan,
1SG Steven Imerman, ,
MSgt Robert "Rock" Aldi, CW5 Jack Cardwell,
MSgt David Hoffman, SSG Michael Noll,
SPC Nancy Greene, CPL Dave Hoover