Anton Tushin/Rostec The claim is sure to raise eyebrows in the world of body armor. While stopping such a big bullet is theoretically possible, the armor would be so bulky that it would be unusable. A new Russian program to modernize the country’s ground forces is promising big advances in body armor technology. And we mean big: The Russian military equipment manufacturer Rostec promises the armor will be able to stop the bullet from a .50-caliber machine gun. Whether a soldier will ever be able to waddle to the front line, however, is a different story. A Russian naval infantryman wearing body armor aims an anti-tank rocket launcher, 2017.