First of all watch this video:
Romney has a habit of flip flopping on the issues. He is not doing that here. He will support gun bans. He talks a good game, but he will not stand up to the anti-gun crowd.
What is a weapon of unusual lethality?
What gun could be described by this statement?
All guns can be described with that statement. Any gun can be used in a lethal manner.
Terms such as this are used to mask a candidates true feelings on an issue.