To people like the OP's "friend" who are so horrified by the thought of "civilians" having the dread power of the so-called "assault rifles" in their hands: rifles with the exact same capabilities have been in the hands of civilians throughout North America for well over 125 years now.
The first truly effective self-loading rifle was probably the Mondragon, which was invented by General Manuel Mondragon of the Mexican Army. He patented it in 1887, although he wasn't able to get it into production until 1901, the same year it went into service with the Mexican Army, which continued to use various models of it until 1949.
Now, just for fun, let's compare the 126-year-old Mondragon rifle used as a military weapon by the Mexican Army with that quintessential terrible, evil modernday tool-of-the-devil "black rifle", the AR-15:
Modern AR-15:
The AR platform is a gas-operated self-loading rifle. It uses gas piped back from near the muzzle to unlock and open a rotating bolt. The rifle comes in both semi-auto only and selective fire versions. (Only the semi-auto versions are available to civilians in Canada). It is loaded with 20- or 30-round box magazines (and also 5-round ones in Canada, where the standard ones must also all be pinned to hold only 5 rounds for civilians.) The most common chambering for the AR (and the one that all the anti-gunners fear because it is "military") is 5.56x45mm Nato / .223. Originally a varmint cartridge and has an effective range of about 400m. The AR also is available chambered in 7.62x51mm Nato / .308 Winchester, a more powerful cartridge with a somewhat greater range.
The AR comes made with a barrel and mechanism of steel, and a stock made of the most modern composite materials in a frightening black colour with a pistol grip.
19th Century Mondragon:
The Mondragon was a gas-operated self-loading rifle. It used gas piped back from near the muzzle to drive a piston system to unlock and open a rotating bolt. The rifle came in both semi-auto and selective fire versions. It was loaded with 8- or 20-round detachable box magazines when it was first introduced into service in 1901, and after 1911, was also available with 100-round drum mags. The most common chambering for the Mondragon was the Mexican service cartridge, the 7x57mm Mauser. However, the Germans experimented with the Mondragon on the Western Front during WW1, and those rifles may have fired the standard German 8x57mm service cartridge. Both these cartridges are at least as powerful and long-ranged as 7.62mm Nato if not more so, and far more powerful than 5.56mm Nato.
The Mondragon was built with a steel barrel and mechanism and a tasteful wood stock of "traditional" appearance.
Conclusion:
In terms of function as a weapon - and in particular, as a dangerous "mass killing" weapon in civilian hands - there is no effective difference whatsoever between the scary black AR "modern sporting rifle" (or "assault rifle" if you're on that side of the fence) and the wood-stocked Mondragon, some of which have been in civilian hands for over a century now.
The Mondragon can fire as fast as the AR; the Mondragon uses detachable magazines as big if not bigger than the standard-capacity AR magazines; and the Mondragon actually fires a round considerably more powerful and longer-ranged than the one most commonly used in the AR.
The only other difference is that the Mondragon, although it was first patented 126 years ago and was used as a military weapon for 48 years, was never demonised as an "assault rifle" that was "too dangerous and too powerful to be trusted in civilian hands".
Now, let's talk about the first commercially successful self-loading hunting rifle - the Remington Autoloading Rifle, later renamed the Remington Model 8. Patented by John M. Browning in 1900, and made in various forms by Remington from 1906 to 1950. Fired various deer-calibre cartridges. Loaded either into a fixed 5-shot magazine, or else used detachable box magazines holding either 15 or 20 rounds. Sold in the thousands in the US and Canada as a hunting rifle and also sometimes as a police weapon.
Effective difference between this rifle and the AR? The modern AR has a plastic stock with a pistol grip; the 100-year-old Remington 8 has a wood stock - that's it.
Semi-auto? Check.
"Large capacity" box magazines for rapid reloading? Check.
More powerful cartridges with greater killing capacity and range than most ARs? Check.
The only other major difference between the rifles? The Remington 8 has never been demonised as an "assault rifle too dangerous to be allowed to remain in civilian hands" - even though it could do anything an AR can do if used in a shooting spree and has been in those civilian hands for over a century.
h you have guns? What do you do with them? 
