Pellets are astablised with spin and their skirt, their stabilising area is much shorter then slugs. Because of the pellet shape, the BC is much lower than the BC of a slugs and the air resistance during flight is lower. Pellets also have a much shorter friction surface in the barrel, therefore they are much more easily pushed out of the bareel than slugs that require a greater impulse in the rear of the barrel, especially if they are spring guns. Slugs
have a hollow point, which provides expansion and improved accuracy. This makes slugs much more suitable for hunting and long range shooting as they carry much more energy downrange.