While most states regulate handguns by requiring a permit for their purchase and possession, rifles and shotguns remain largely unregulated in the United States. They are sold in sporting goods stores, gun shops and through online directories that bring gun buyers and sellers together.
One directory even has listings for rifles with "sniper scopes" and a "flashhider," used to hide the shooter's location from observers.
In the wake of the this week's highway sniper spree in Indiana, for which a 17-year-old has been charged, proponents of bills in Congress to tighten gun regulations say that powerful guns in the wrong hands present a danger to the American public.
In Indiana, like Ohio where sniper shootings took place in 2004, all that is required to purchase a rifle at a store is a criminal background check of felony convictions and insanity pleas.
But these background checks are not enough, according to Rep. Carolyn McCarthy (D-NY).
McCarthy is currently sponsoring two bills in the House, one which would provide federal funds to update the background check program and the other which would prevent people on terrorist watch lists from purchasing firearms.
She said the bills would "protect second amendment rights," by preventing people who are precluded from purchasing firearms from obtaining them due to errors in the courts' reporting system.
"There is no bill, in my opinion, that would take away the right of a law-abiding citizen to buy a gun," she said.
Also being proposed in the House and Senate is a ban on large .50 caliber sniper-type rifles in the United States, but those proposals remain in committee.
Opponents of that bill and others say they violate the second amendment. The NRA says that the ban would be unnecessary because ".50 caliber rifles are virtually unheard of in crime," saying that their size, weight and high cost make them impractical for would-be criminals.
An NRA fact sheet on the .50 caliber ban said that the bills were supported by "Anti-gunners," who "are just trying to manufacture an issue to rejuvenate their gun-banning agenda."