A seemingly simple transaction at a gun store in Tucson, Ariz. has turned into a major talking point in the national gun control debate.

Mark Kelly — a retired astronaut and husband to former Rep. Gabby Giffords, who was nearly killed in a mass shooting two years ago — was denied the purchase of a semiautomatic rifle. Kelly had planned to buy it and then turn it over to the Tucson police — a demonstration of how easy it is to buy assault weapons, according to Politico. The purchase was canceled about halfway through a mandatory 20-day waiting period.

Here's how Doug MacKinlay, owner of Diamondback Police Supply, framed the scuttled purchase, via his Facebook page:

While I support and respect Mark Kelly’s 2nd Amendment rights to purchase, possess, and use firearms in a safe and responsible manner, his recent statements to the media made it clear that his intent in purchasing the Sig Sauer M400 5.56mm rifle from us was for reasons other then for his personal use. In light of this fact, I determined that it was in my company’s best interest to terminate this transaction … [Facebook]

Kelly certainly made no secret of his intentions. "It is actually pretty easy," he told CNN's Wolf Blitzer about purchasing the rifle. "You know, for a weapon that's so deadly and really designed for the military, especially with the high-capacity magazines, it is a pretty easy thing to do, even with a background check."

In an op-ed at Politico last month, Kelly pushed for stronger background checks, claiming that the "NRA leadership has decided to dig in and — against all evidence and common sense — preserve a system that makes it easier for criminals to get guns."

Diamondback Police Supply's Facebook page is filled with posts supporting (and a few criticizing) MacKinlay's decision:

And while Kelly might not get his gun, he will, at least, be getting a refund.