"What are the main differences between AK47 and AR15 given that they are both manufactured and not modified for comparison sake and that they have the same auto or semi-auto capability?"
This is the debate (sometimes heated) that happens every second Tuesday of every month around here...
The AK guys calling the AR guys 'Poodle Shooters',
The AR guys calling the AK guys, 'Lead Wasters'.
Pretty accurate on both counts actually...
So the question is actually about the rifles as they fall off the assembly line...
That's really easy,
AK-47 is a true 'Assault' weapon, shortened rifle caliber, in this case a .30 cal., gas assisted piston operation with locking bolt, full auto capable.
Reliable, albeit not particularly accurate, short and medium range weapon with good penetration and 'Knock Down' power.
The AK was intentionally designed to be a battle rifle, easy to manufacture from common materials, have large clearances and tolerances so thermal expansion & contraction, dust, powder residue, ect. wouldn't cause stoppages in combat.
The AK is quite effective at ranges up to 300 yards, but is not particularly accurate by to days standards.
Since it is a 'Combat', standard issue rifle, it must be noted that in study after study of combat after action reports, most soldiers won't engage a target FIRST unless that target is under 75 yards away...
Most soldiers won't engage a target with ACCURATE, AIMED fire even after being fired on, at ranges over 150 yards...
So the AK was particularly effective at that 75 to 150 yard range, exactly as designed!
The AK was also designed for an army that practices 'Target Saturation' and 'Attrition Advances' in battle.
The AK lends it's self well in 'Insurgent' campaigns where irregular and poorly trained and/or educated combatants will be using the rifle.
The US Military practices 'Accurate, Aimed Rifle Fire' and team maneuvering, not human wave attacks...
The AK is perfectly designed for it's intended purpose. (Killing people at short ranges.)
I would like to point out that we don't really have a problem in this country with 'Waves' of deer size animals throwing themselves at us...
And it's too inaccurate and/or under powered in factory trim for 'pinpoint' or longer range hunting of smaller game.
A word should be said about later versions of AK variants for civilian use.
China made thin walled stamped receivers and pinned barrel versions are junk at best, and dangerous at worst.
Inferior machining, inferior base materials, and improper design & fit make these 'civilian' versions a menace to everyone around them when they are fired.
AR 15 is a civilian version of the military M-16.
It was designed by an aircraft company using the latest (at the time) in materials and manufacturing, and is inherently accurate because if the ammunition chosen and the complex modular design.
It is a fully gas operated locking bolt design with no mechanical assist.
The AR-15 wasn't originally designed as a full auto weapon, but was later adopted to full auto.
It's a full size rifle that shoots a highly accurate .22 cal. (.223 or NATO 5.56x45mm) round designed to kill small, thin skinned game and 'varmints'.
It is very reasonably accurate from the factory, but can be very particular about ammo types and cleaning routines.
The factory rifles are accurate, fast into operation, rugged, reliable, made from very good quality materials with very high standards and will reliably drop small and most intermediate size game animals with little or no problem.
Since they use modern materials and designs that use automated machining practices, the price is very reasonable for a highly accurate, safe rifle.
There are no 'Unsafe' AR manufacturers that I'm aware of, although some have better materials & quality control than others.
The AR has the added bonus of being standardized and modular, so after market specialty items grow on trees, and a lot of them actually work as advertised.
The best of both worlds is an AR-10 in .308 Win. or .300 WSM. caliber.
The AR-10 in NATO 7.62x51mm (.308 Win. to civilians) was an issue combat rifle in at least 10 countries and has a cult like following among Egyptian and Israelis snipers that see a lot of action.
A .30 Cal round capable of killing any animal in north America, with the light weight, speed, reliability, and inherent accuracy of an AR rifle.
Also, let's not forget the after market parts machine in this country that can crank out some pretty cool things for AR-10's!