Why are AR-15 and similar legal for private use
To start this , we need to except portions for the HELLER Supreme Court decision to place everything in context.
DISTRICT OF COLUMBIA ET AL. v. HELLER CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT No. 07–290. Argued March 18, 2008—Decided June 26, 2008 (http://www.supremecourt.gov/opinions/07pdf/07-290.pdf)
SCALIA, J., delivered the opinion of the Court, in which ROBERTS, C. J., and KENNEDY, THOMAS, and ALITO, JJ., joined. STEVENS, J., filed a dissenting opinion, in which SOUTER, GINSBURG, and BREYER, JJ., joined. BREYER, J., filed a dissenting opinion, in which STEVENS, SOUTER, and GINSBURG, JJ., joined.
In reading the selected passages, “Miller” is a previous decision. Selected passages from the Heller Decision:
We therefore believe that the most likely reading of all four of these pre-Second Amendment state constitutional provisions is that they secured an individual right to bear arms for defensive purposes.
We may as well consider at this point (for we will have to consider eventually) what types of weapons Miller permits. Read in isolation, Miller’s phrase “part of ordinary military equipment” could mean that only those weapons useful in warfare are protected. That would be a startling reading of the opinion, since it would mean that the National Firearms Act’s restrictions on machineguns (not challenged in Miller) might be unconstitutional, machineguns being useful in warfare in 1939. We think that Miller’s “ordinary military equipment” language must be read in tandem with what comes after: “[O]rdinarily when called for [militia] service [able-bodied] men were expected to appear bearing arms supplied by themselves and of the kind in common use at the time.” 307 U. S., at 179. The traditional militia was formed from a pool of men bringing arms “in common use at the time” for lawful purposes like self-defense. “In the colonial and revolutionary war era, [small-arms] weapons used by militiamen and weapons used in defense of person and home were one and the same.”
We therefore read Miller to say only that the Second Amendment does not protect those weapons not typically possessed by law-abiding citizens for lawful purposes, such as short-barreled shotguns.
We also recognize another important limitation on the right to keep and carry arms. Miller said, as we have explained, that the sorts of weapons protected were those “in common use at the time.”
We think that limitation is fairly supported by the historical tradition of prohibiting the carrying of “dangerous and unusual weapons.” It may be objected that if weapons that are most useful in military service—M-16 rifles and the like—may be banned, then the Second Amendment right is completely detached from the prefatory clause. But as we have said, the conception of the militia at the time of the Second Amendment’s ratification was the body of all citizens capable of military service, who would bring the sorts of lawful weapons that they possessed at home to militia duty. It may well be true today that a militia, to be as effective as militias in the 18th century, would require sophisticated arms that are highly unusual in society at large. Indeed, it may be true that no amount of small arms could be useful against modern-day bombers and tanks. We identify these presumptively lawful regulatory measures only as examples; our list does not purport to be exhaustive. But the fact that modern developments have limited the degree of fit between the prefatory clause and the protected right cannot change our interpretation of the right.
Thus in this ruling, it very specifically mentions the M-16 rifle as permissible. The AR-15 and its relatives are commercially versions of the M-16. The AR-15 and relatives are in common use presently. Thus since the US allowed private purchase of semi-automatic weapons such as AR-15 they are legal devices for self-defense and now in common use , and machine guns (i.e. automatic weapons) or sawed off-shotguns which were prevented by federal law from getting into common use are not permitted.
History of AR-15/M-16: The AR-15 was first built in 1959 by ArmaLite as a proposed small arms rifle for the United States armed forces. Because of financial problems, ArmaLite sold the design to Colt. After some modifications, the redesigned rifle was adopted in 1969 as the US military M16 rifle. In 1963, Colt started selling the semi-automatic version of the rifle for civilians as the Colt AR-15. Although the name "AR-15" remains a Colt registered trademark, variants of the firearm are made, modified, and sold under various names by multiple manufacturers.
Do these weapons or similar make the US population safer?
I performed a quick research related to the question- Is the addition of the AR-15 and similar semi-automatic weapons to the US gun population made the US "safer" by decreasing the US murder rate. I could not find any refereed high quality research related. I could not find any reporting of the use of an AR-15 type weapon for defensive home use against an attacker that could not have the same outcome with something old fashioned like a pump action or double barrel shotgun. I then picked the interval from 1950s thru 1980s as an interval when probably semi-automatic weapons similar to the AR-15 were not in common use within the USA. I could not find mass murders in the 1950s thru 1980's before AR-15s and similar came into common use with guns like is occurring presently.
Proposed Research Project: Can it be shown that the addition of weapons such as AR-15 and similar weapons to the US gun population has decreased the US murder rate of non-family members or relatives? Or did the murder rate increase. This question is focused to the use of these weapons outside of a person's house/private property. This would be a great research project for various institutions. With this research possibly a rational future can be obtained.