The weight of the Monster Exact Diabolo pellets have been chosen to fit the most powerful air rifles currently available on the market. It is a really heavy weighted pellet that is stable even at higher power levels. A top choice for airgun hunters. Also check out the new Diabolo Beast if you're looking for something even heavier. These .177 caliber Monster Exact pellets weigh in at 13.43 grains- which will do the job if you like to hunt or do pest control with magnum air rifles or precharged pneumatic airguns.