To give a little bit better description of what I have in mind, take a good look at some of the tshirt designs on ZeroFoxtrot.com. They have some very cool, very detailed designs with hats, headdresses, and such over a skull. Designs like their Ronin, Patriot, Bushido, or even Sons of Liberty are REALLY what I have in mind.
Something that will grab the viewer's attention with the skull design, then they notice the business name, Heavy Metal Ordnance or Heavy Metal Firearms, which ever you think would look better. Technically, the business name is Heavy Metal Ordnance, but the domain I'll be using on all advertising is HeavyMetalFirearms.com as I was worried people would misspell Ordnance.
Take your pick.
Grab 'em with the skull design, then land 'em with the business name!