A Space marine Bolt Rifle was widely used in the Space Marine forces that fought more than 500 different kinds of races, orks, Eldar, Chaos, Tau, Imperial Guard, Necrons and other races. Comparing to the .40 magnum bullet and .50 caliber round to the Bolt round which is not a grenade launcher round. Here is a photo of a Space marine holing his bolt gun [link]
Those Bolt Rifle can shred a M1A1 Abram in less than 20 seconds with full clip magazine. Very heavy for a normal soldier to carry. Only for the superhuman soldiers with heavy armor to support the weight basically makes them a walking tank. [link]
A war that you cannot survive in less than one minute with a normal soldier. The Space marines have been around for nearly ever since the legends begin to grow. They only fight for the good of their powerful god, The emperor.
Comparing the bullets to the Space Marine rounds, think you can survive from one shot?
Done by me on Pimp my Gun.