they could just use a blended metal bullet. I dont remember off hand what metals are blended in the projectile. But I read an article in stars and stripes where a company donated some blended metal bullets 5.56 and were used on patrol. They shot an insurgent with it in the stomach, normal this wasn't life threatening but it blew his backside out. then there was a frenzy to get ahold of allthe blended metal bullets they could find. But the Army said they will not use those bullets. oh wait I found the article
http://www.armedforcesjournal.com/bullets/
Where can I purchase a case of these rounds?