There is no difference. The list for rifles is the following:
Folding or telescoping stock - certain hunting rifles have these
Pistol grip - certain hunting rifles have these
Bayonet mount - when has a criminal ever fixed a bayonet?
Flash suppressor, or threaded barrel designed to accommodate one - what difference does the use of one of these make?
Grenade launcher (more precisely, a muzzle device that enables launching or firing rifle grenades, though this applies only to muzzle mounted grenade launchers and not those mounted externally) - it was for a WWII grenade launcher, but regardless, one can't buy the grenades for either one anyhow
None of the above has anything to do with the ability of the gun to kill.
It is not nonsense at all. The term "assault weapon" as we know it now was created by gun control activist Josh Sugarmann. It has nothing to do with the weapon's functionality. And "hunting rifles" are not guns that "used to be the same" as military weapons. They are the same guns that the military used, albeit just with certain features that make them more suited to hunting. Even this gets arbitrary, as many of the same features that make guns ideal for military and police use also make them ideal for hunting use.
Here are some modern hunting rifles:
Remington R15
Smith and Wesson 300 Whisper
http://www.smith-wesson.com/wcsstore/SmWesson2/upload/images/firearms/detail_md/811300_01_md.jpg
Note these look identical to many an AR-15, which is many ways they are, but they have a camouflage pattern for hunting and some extra more hunting-oriented features. But functionally there's not really any difference.
The military does not use different guns today unless you mean machine guns, which are more for suppressive fire purposes. Otherwise, the military's guns have the same functionality as any semi-automatic rifle one can buy. One of the first semi-automatic rifles was the Winchester 1903 (came out in 1903 hence the name). The M1 Garand is a semi-automatic WWII rifle and the Springfield M1A is a 1950s-era weapon. The AR-10 and the AR-15 are late 50s to early 60s.
The military does use 30 round magazines, which as said, one can argue for limiting the magazine size to ten rounds.
No, because there is no such thing as a "military-type" weapon in terms of killing ability. A gun is a gun is a gun. It doesn't care if it's being used to shoot people or animals. Here is a sniper rifle used by the military, the M24:
Here is the Remington 700 hunting rifle, which is what the M24 is based off of:
http://www.remington.com/~/media/Images/Firearms/Centerfire/Model-700/Model-700-BDL-Anniversary/700_7mm_50th_BDL_84063_Right.ashx?w=570&bc=black
Neither gun cares whether it's shooting a bear or a person.
Remember though that the Second Amendment isn't about hunting. For example, weapons like the AR-15 are also excellent for home defense purposes. That said though, while I can see the arguments about magazine capacity, I do not at all see what the stock has anything to do with the gun's ability to kill something. As for silencers, silencers do not silence a gun shot, that is just Hollywood where that happens.