Not an expert here, but I believe it's the bit of a nuclear warhead that squashe...

		mgarfias on May 10, 2013 \| parent \| context \| favorite \| on: State Department Demands 3-D Gun Blueprints Be Rem... Not an expert here, but I believe it's the bit of a nuclear warhead that squashes the plutonium pit and causes it to go critical.