"It's probably a combination of the cartels, a combination of the war, a combination of possibly hoarding in terms of panic, wondering what's going to happen," said Barry Bogle, director of the El Paso Community College Law Enforcement Training Center. The "wondering" is on the part of gun owners who worry the Obama administration will impose tighter gun and ammunition controls. Experts agree wartime activity in Iraq and Afghanistan has depleted the U.S. supply.

Bogle is a retired El Paso police officer who now helps students who want to qualify for jobs on police forces. The academy and shooting range also offers the concealed handgun training course required for Texans who want to carry their guns. "We've had calls from people that have registered for the course calling back and saying I can't find any ammunition for my gun to attend the course."

Gun dealer Harold Shirley sees it all the time at "Sun City Guns" in El Paso, "I spend a lot of time telling people no instead of yes I can help you. Any businessman who does that for very long is out of business." The largest ammunition retailer in the country Wal-Mart has started rationing at some stores on the border limiting customers to six boxes per person per day.

You wouldn't suspect there's a shortage by looking at crime scenes in Mexico, especially in Juarez where gun violence is once again climbing. There's a lot of ammo on the streets and plenty of bodies to prove it -- despite Mexico's tough gun control law. According to Juarez Police on Monday in two separate incidents suspects abandoned several rounds of ammunition on a public streets, possibly to evade authorities after making a hit. In one incident someone dumped 130 rounds of "different calibers" in broad daylight.

I asked an ATF agent who works on the El Paso-Juarez border about the illegal trade. "The sale on the open market, there's no background required. None of that is required," he explained. This agent works Mexico cases so for security reasons I won't use his name. Unlike guns, to buy ammunition you only need to look 18 -- no questions asked, no id required unless the sales person wants to check if you are a minor or a legal resident.

There's no way to know how much the drug cartels are buying on the border. What is clear, a spike in prices won't stop their hit squads from loading their weapons." Again, if we're talking about cartel people, they're people who generally speaking have a lot of money available for purchasing whatever tools of the trade they require, "is how the ATF agent put it.

On the U.S. side gun owners are bracing for summer of scarcity and high prices says Sun City Guns' Shirley. "Ammunition that we were selling for 11 dollars a box last summer, we're now selling for $33.00 $34.00. That's a jaw dropper for people who aren't aware."

The Law Enforcement Training Academy has a good supply since the college orders its ammunition a year in advance. Academy Director Bogle hopes the shortage eases soon. "I'm just keeping my fingers crossed like everyone else is that it's going to get better and not worse." If the trend continues -- it will only get worse this fall -- that's when hunting season begins.