Kinda depends upon what time frame you're looking at when defining an "ASSAULT RIFLE" . .
What is an "ASSAULT RIFLE" ?
Based upon Diane Fienstein's Rules, an M-1 Garand doesn't fall into their categories . .
It's an Eight Shot, Semi-Auto, internal magazine holding no more than eight shots, .30 US (30/06 Springfield) caliber . . . But, from 1942 until it was "phased out" in 1965, it was the primary Infantry "ASSAULT RIFLE" . . And still is, as a Ceremonial Assault Rifle, usually seen being used in color guards, often nickel plated.
Or . . You can still buy, from "The Springfield Armory", a '03-A3 Springfield Bolt Action Rifle, .30 Gov (30-06), 5 round internal magazine, Used by the United States military forces as the Primary Assault Rifle from 1908 until phased out in the middle of WWII.
Or . . An 1859 Sharps Rifle, single shot, breech loading, .52 caliber, used by the US Army from 1860 until phased out in 1881 . . .
So, one would be led to believe that it would be in the eye of the beholder
I'm not even too sure what the real definition of an "ASSAULT RIFLE" really is, because both need and technology change the actual weapon almost yearly. a "loose" definition might be: A firearm that can be fired from the shoulder or hip, with selective fire capabilities (Safe, single, 3 shot burst and fully auto), external magazine of optional capacities, and technology has mandated the addition of the "Picatinny Rail" Mounting system, so that different sighting means and other optional items can be "universally Attached" . . Makes 'em ugly, but versatile . .
And the current Hearthrob "Assault Rifle' isn't a legal rifle at all, but a "Handgun" by the current Federal description of handguns V. long guns . . We're speaking of the M-4 "Carbine", a M-16 frame and receiver with a 16" barrel and either no stock or the optional "Skeleton Stock" that folds away . . . It's what all the SEALs and SOF guys are wearing today . . And all the "gamers" use in their video games . .