Suggested by itcheyness
1000 ACS troopers (Legacy of the Aldenata, first time here) will go up against 1000 Space Marines (Black Templars, Warhammer 40K).
The ACS troops are organized as a typical ACS battalion, and the Space marines are organized as a typical chapter (with all of the captains, chaplains, and apothecaries that they would have as codex standard) with the exception of having no librarians.
Both sides have access to all weapons that they would normally be expected to use in battle, with enough ammo to not have to worry about running out.
Both sides are fighting solely as infantry.
Which side wins?