In Tennessee, Bob Armentrout ws cleared to buy a handgun but was rejected when he tried to buy a shotgun. He isn't alone in his frustration, reports The Tennessean. Tennessee has the highest rate of gun purchase denials in the U.S., rejecting in 2010 4.3 percent of gun buyers' purchases based on state criminal background checks, more than twice the national average. A majority of those who appeal their cases win. It's a system that annoys both buyers and sellers and could become an even bigger headache if new federal efforts to require background checks for all gun sales are successful. “I can't even imagine how they're even going to keep up with the processing,” Armentrout said. “They can barely keep up now.” The Tennessee Bureau of Investigation, which conducts a $10 background check on all gun purchases from gun stores, acknowledges it has a high denial rate. Spokeswoman Kristin Helm says the TBI Instant Check System, or TICS, is great for recording arrests but doesn't always get updated as to the outcome of those cases.