I think it’s all been said, but if you are going to use the name or likeness of a product called M-16, then make your own art, it’s OK.
If you use Colt’s 3DS Max model in your game…not good. And try to avoid making statements in your descriptions about weapons.
Make all the comments you want about the ammo they use…(Wink, wink). Also avoid going online to get descriptions and fire rates
like EA does in Battlefield. Make your own. Use your head, talking about or showing your own art of a product does not infringe on
anything. And using the “M” in front of a weapon only indicates “military” and should be fine, calling it a “Colt this or that” could be
problematic. (Not a lawyer). Hold several US Patents.