Meh, let them, if you're going to spend millions on projectile science (which isn't anything new, what you you crying about? This kind of projects are happening all the time) why not let it be a bit more environment friendly.
Since you are completely missing the point. People killing people alone is not bad for the environment. But people tend to destroy a lot more then just the people they where aiming for. And a bullet left in nature is, as you can read, toxic for the environment. I can imagine that a heavy gun fight can be pretty bad for the groundwater or futility of the ground. But then again, I don't really know, because bullets are pretty small, even in large amounts they'd be spread rather wide to cause real damage.
Meh, /care.