The difference between the Glock 19 and the Glock 19C is compensated barrel on the 19C. The 19C model has two apertures cut into the slide, between the chamber and the muzzle. These gaps allow the gas release then the gun is fired, which results in reducing the muzzle rise and recoil. Further, it means faster recovery time between shots and a more controllable gun, but also an increased noise level, which might be deleterious in enclosed areas (like a car or similar). The magazine capacity is 15-rounds standard, and mags drop free, unlike the earlier Glocks where the mags had to be physically removed from the frame. The grip is customizable, to accommodate any hand size.