Loads, Grains, and Bullets
From Free Knowledge Base- The DUCK Project: information for everyone
With modern firearms the term "grains" refers to weight. The term itself is a throwback to the black powder era. On a box of ammunition cartridges the term "grains" describes the weight (mass) of the bullet.
If you purchase a box of a .30-06 rifle cartridges you will note that the load is marked on the box described by grains.