I'm totally for it! When they are old enough they even go hunting with their dad. Someday, they could be soldiers. Who knows? But we teach them gun safety and they know guns are serious business. So as far as toy guns go, it's just a boy thing and they love to pretend they are finding bad guys. I love that.
If you don't let them play with 'guns' they will find another way... something forbidden is always more interesting. If not toy guns, then Lego guns, if not Lego guns, then sticks or their fingers. Teach them right and safety rules and it will go a long way. And be safe with your own guns.
As the mom of four boys, you know, they will find a way. Its in their nature to protect and defend their home and women!! Whether its guns, swords or just putting the smack down on a stuffed bear.