EDIT: I see my post is being downvoted. I know that it may come across as insensitive to immediately leap to the gun control debate, but frankly I'm more angry than upset by this news. How many times does it have to happen? We have a good 48 hours of emotional outpouring and then everyone forgets it ever happened.
Where exactly do I make that assumption? You'll notice that I didn't even call for a blanket ban on guns, just that, as a nation, we could actually sit down and have a serious talk about whether people should be able to own weapons like this one for private use:
[EDIT: I regret posting the link to the rifle, there's clearly plenty of debate about it that detracts from the main topic of discussion- and we don't know any details for definite.]
As a nation, we've decided that we don't want to restrict the rights of hundreds of millions of law abiding citizens merely because a few people misuse those rights. This is why politicians have generally decided not to push for more gun control - it's an election losing issue.
Incidentally, I'm confused by the point of that tweet. Here are some other .223 rifles:
http://s845.beta.photobucket.com/user/OldColdWarrior2009/med...
http://media.liveauctiongroup.net/i/9380/10373165_1.jpg?v=8C...
http://molot.biz/product-e/vepr223-super.jpg
For most calibers, you can find guns with many different form factors that accept bullets of that caliber. So what?