From the Post homepage:
"Technicality"? The guy didn't bring the gun with him. To quote the story: "Police explained to Heller that he needed to show officials the guns he wanted to register -- and allow them to be test-fired -- as part of the registration process." Right. So, if you want to register a gun, you should bring the gun with you. Hardly a picky detail. One might even say, freaking obvious. Also, it appears from the story that the guy knew he had to bring the guns to get them registered. I don't think "technicality" fits.
(I'm guessing the people who write blurbs for the front page are far, far away - a whole state away, probably - from the people who write and edit the stories.)