Meplat, from a French term for a flat surface, is the technical term for the tip or nose of a bullet. The shape of the meplat is important when determining how the bullet will move through the air.[1][2] If uneven, the bullet will not have an ideal flight characteristic and will most likely not be of the expected weight for that type of round. Rounds that have the same shaped meplat will travel through the air in a nearly identical fashion, making it easier to group shots together or hit a target multiple times.
Trimming the meplat also makes the bullet shorter. This makes the round more susceptible to wind drift. So even though the grouping will be better the range will be slightly less than before.
Bullets of the same caliber but with different-shaped meplats sometimes cannot be loaded into the same firearm. The meplat plays an important role in the loading of a weapon whose ammunition is guided into the chamber by a mechanism (e.g. auto-loading, lever action or bolt action), though this usually is not important in weapons whose rounds are chambered by hand (e.g. single shots, double rifles, drillings and revolvers) and not by a mechanism.