Not entirely true E1Operator. Colt already fought and lost the "trade dress" (likeness) issue some years back (2005-2007).....against Bushmaster.
http://www.bushmaster.com/press_release%20120905.asp
Umarex is a licensing company which H&K has given their trademark (and trade dress rights, such as they are) to who then subcontract firearms companies (airsoft and otherwise, i.e. BB gun makers) to manufacture licensed legal replicas of H&K's designs.
Typically, part of trade dress infringement cases is that you have to prove
functionality of the likeness of your gun. If something is purely cosmetic, then it doesn't legally fall under trade dress protections. H&K does not manufacture airsoft guns and they never have, so they don't have any copyrights of the function of airsoft guns or their components. The only thing they have is a copyright on their names and model designations. Remember that it has to not only look like a duck, but it must also walk like a duck, talk like a duck, and act like a duck to be a duck.
Second, Umarex does not manufacture guns of any kind. They contract other companies to make airsoft guns to their specifications and to print any trademark on which they have a license to use. Umarex could actually make airsoft AUGs and put H&K on them if they wanted to. A bad example, yes, but just an example. Umarex can only protect the H&K trademark, not the trade dress. Colas (sodas) are not owned by Coca-Cola....you can get colas from other sources that look, smell, fizz, and even kinda taste like Coca-Cola. Not infringement.
To this end I note that Ares, formerly an Umarex H&K licensee, already dropped the G-36K moniker and H&K trades on their newly renamed "AS-36K".
http://www.popularairsoft.com/news/ares ... ion-review
Similarly, Vector Arms (and Special Weapons, Inc., PTR Industries, Coharie Arms, Rapid Fire, RedRock Arms, GSG, American Tactical, plus half a dozen others, etc.) make 'unlicensed' real steel copies of the MP-5.
http://www.atlanticfirearms.com/index.p ... gory_id=23
No trade dress issues.
This matter took over 4 years to settle, btw. Umarex actually bought the H&K trades back in early 2008....it just took this long to get a judge to agree to their trademark ownership.
http://www.airsoft-barracks.com/forums/ ... e-vfc-416/