HARLINGEN – Police said the Las Vegas gunman had at least 17 firearms in his hotel room.

A Harlingen gun store owner told CHANNEL 5 NEWs as long as you pass an FBI background check, it's pretty simple to obtain a semi-automatic rifle or handgun in Texas.

"It's very difficult to specify the type of weapon used," said Brian Guerra, who owns Lone Star Guns and firearm manufacturing company Armas de Guerra in Harlingen.

Guerra said there are easy, legal ways to make a consumer weapon fire rapidly. He showed us one, a completely legal binary trigger modification.

He compared the sound to the Las Vegas shooting videos.

"The person either had a very fast trigger or he had some sort of slow rate of fire machine gun,” Guerra said.

The Federal Bureau of Alcohol Tobacco and Firearms tracks weapons registered under the National Firearms Act.

These weapons are considered the most dangerous. Texas has the highest number of weapons registered on the list with 588,696 for 2017. Close to 36,534 are machine guns, as defined by the ATF.

Guerra said machine guns are hard to come by, expensive and highly-tracked. They were banned to manufacturing in the 1980s, but can still be traded.

In contrast, people can purchase semi-automatic weapons with ease.

“Buying a standard handgun or semi-automatic rifle or hunting rifle, it's a fairly simple process you fill out a background check,” Guerra said. “That background check gets called into the FBI and then the FBI will tell us as dealers whether or not the person can legally purchase a firearm.”

Guerra said there is one problem: consumers can buy kits online or at gun shows to convert semi-automatic weapons to fully-automatic. He said the sale of the kits is not banned.

"You can purchase those parts, but if you purchase those parts and convert your weapon, that is 100 percent illegal. It is not allowed, you will go to jail for a very, very long time and the government takes that very seriously,” Guerra said.

Guerra said his heart goes out to the victims regardless of what types of rifles were used.

"My sister-in-law and my niece just came back yesterday,” Guerra said. “They were just there. It touches home. It's very frightening knowing that you had family that close there." 

Guerra said the background checks take as little as five minutes and as long as three days if there are any complications, including people who try to buy a gun with a common name.

Gun purchasers are able to skip an FBI background check if they hold firearms permit with Texas. 

The FBI offers a list of reasons why potential gun owners will be disqualified under their background checks:

• A person who has been convicted in any court of a crime punishable by imprisonment for a term exceeding one year or any state offense classified by the state as a misdemeanor and is punishable by a term of imprisonment of more than two years.
• Persons who are fugitives of justice – for example, the subject of an active felony or misdemeanor warrant.
• An unlawful user and/or an addict of any controlled substance; for example, a person convicted for the use or possession of a controlled substance within the past year; or a person with multiple arrests for the use or possession of a controlled substance within the past five years with the most recent arrest occurring within the past year; or a person found through a drug test to use a controlled substance unlawfully, provided the test was administered within the past year.
• A person adjudicated mental defective or involuntarily committed to a mental institution or incompetent to handle own affairs, including dispositions to criminal charges of found not guilty by reason of insanity or found incompetent to stand trial.
• A person who, being an alien, is illegally or unlawfully in the United States.
• A person who, being an alien except as provided in subsection (y) (2), has been admitted to the United States under a non-immigrant visa.
• A person dishonorably discharged from the United States Armed Forces.
• A person who has renounced his/her United States citizenship.
• The subject of a protective order issued after a hearing in which the respondent had notice that restrains them from harassing, stalking, or threatening an intimate partner or child of such partner. This does not include ex parte orders.
• A person convicted in any court of a misdemeanor crime which includes the use or attempted use of physical force or threatened use of a deadly weapon and the defendant was the spouse, former spouse, parent, guardian of the victim, by a person with whom the victim shares a child in common, by a person who is cohabiting with or has cohabited in the past with the victim as a spouse, parent, guardian or similar situation to a spouse, parent or guardian of the victim.
• A person who is under indictment or information for a crime punishable by imprisonment for a term exceeding one year.