A federal court judge has ruled that AR-style rifles and AK-47 semi automatic rifles are "dangerous and unusual" firearms and are not protected by the second amendment.

In a case brought before the U.S. Court of Appeals in Maryland, gun rights groups claimed a recent law banning many semi-automatic rifles and AK-47 variants didn't pass constitutional muster, arguing the firearms were commonly possessed and used for lawful purposes such as home defense or sport.

The pro-gun groups also challenged the state's ban on purchasing standard capacity magazines over 10 rounds.

United States district judge Catherine Blake was not convinced, saying in her opinion the banned "assault long guns" were only owned by a small fraction of the shooting public and that opponents couldn't demonstrate a single use of that type of arms in self defense.

"The court seriously doubts that the banned assault long guns are commonly possessed for lawful purposes, particularly self-defense in the home, which is at the core of the Second Amendment right, and is inclined to find the weapons fall outside Second Amendment protection as dangerous and unusual," Blake wrote in her August 12 opinion. "Despite the plaintiffs’ claims that they would like to use assault weapons for defensive purposes, assault weapons are military-style weapons designed for offensive use, and are equally, or possibly even more effective, in functioning and killing capacity as their fully automatic versions."

Blake did admit that the Maryland law banning 45 named "assault weapons" and so-called "large capacity magazines" does burden the Second Amendment rights of the state's citizens, adding other courts would have to determine if the weapons and magazines were "useful or commonly used" for lawful purposes.

The case hinged on the previous Heller decision which overturned Washington, D.C.'s ban on handguns. In that case, the Supreme Court said a ban on an "entire class" of firearms -- such as all handguns that are commonly possessed for defense of the home -- was unconstitutional.

The ruling follows a similar one in January that upheld Connecticut's ban on AR-style rifles. It is unclear what effect the ruling will have on gun rights in Maryland or whether it will embolden anti-gun forces to impose more restrictions.

Pro-gun groups vowed to appeal to the 4th Circuit Court.