Dog Gone at Penigma would have us believe that there are people out there somewhere claiming that there is no difference between a .22LR cartridge and a .223 Remington cartridge.
Dog Gone at Penigma posted a picture that definitively proves that there is indeed a difference between the two cartridges.
Q.E.D. wing nuts:
Sat Feb 9, 2013, 02:14 PM
Dog Gone at Penigma (412 posts)
Disingenuous Argument (in more simple terms, FALSE argument)
The text which accompanied the photo I found salient to discussion of gun control restricting certain kinds of more damaging ammunition. I find myself rolling my eyes when someone makes the disingenuous argument postered below.
The .223 cartridge contains significantly more powder than the .22LR cartridge (maximum pressure 24,000 PSI for .22LR; maximum pressure 50,000 PSI for .223). The .223 bullet is a much heavier bullet, travelling at a higher velocity. This means that the .223 bullet has much more energy to deliver on its target.
Upon impact .223 bullets demonstrate a tendency to tumble, increasing the size of the wound channel. The .223 bullet also delivers additional damage due to hydrostatic shock. The .22LR bullet has neither of these qualities.
This pretty much sums up the difference:
http://www.thefirearmblog.com/blog/2011/05/03/guest-post-22-lr-vs-223-rem/

In all fairness, there was one DUmmy that called Dog Gone at Penigma on his/her BS.
Response to Dog Gone at Penigma (Original post)Sat Feb 9, 2013, 02:42 PM
ProgressiveProfessor (20,745 posts)
6. Who makes that argument? I have never seen it made in serious conversation
Click here to purchase valentine hearts!
I've never heard it either, Professor. But for any DUmmies out there that still aren't sure:
Take a .22LR cartridge and push it into your ear, with a little force you can probably get it all the way in. A .223 Remington cartridge, on the other hand, will probably get stuck at the cartridge neck.