maximum projectile velocity (Vmax) is higher than the real muzzle velocity (Vr). The external ballistics uses so-called initial velocity Vo, which is not the same as the real muzzle velocity. The initial velocity Vo is calculated via an extrapolation of the decaying part of velocity curve to the position of the muzzle (to). The difference between these two velocities is visible in the chart. Altering transitional ballistics In addition to the process of "crowning" a barrel to ensure a clean and accurate exit of the bullet, there are a number of devices that attempt to harness the muzzle blast for various reasons. Suppressing the blast Flash suppressors and sound suppressors are the most obvious devices that operate in the transitional ballistics realm. These both alter the flow of the escaping gas to reduce the effects of the muzzle blast. Flash suppressors introduce turbulence into the mixing of fuel-laden hot gases escaping from the muzzle and the surrounding oxygen-rich air, reducing combustion efficiency and thus reducing the size and brightness of the flash. Sound suppressors slow the expansion of gases, allowing it to cool and reducing the rate at which it escapes to prevent a shockwave from forming. A recoil compensator is designed to direct the gases upwards at roughly a right angle to the bore, in essence making it a small rocket that pushes the muzzle downwards, and counters the "flip", or rise of the muzzle caused by the high bore line of most firearms. These are often found on "raceguns" used for action shooting and in heavy, rifle caliber handguns used in metallic silhouette shooting. In the former case, the compensator serves to keep the sights down on target for a quick follow-up shot, while in the latter case they keep the heavy recoil directed backwards, preventing the pistol from trying to twist out of the shooter's grip. A muzzle brake is designed to redirect the muzzle blast backwards, and therefore counter the recoil of the bullet. Muzzle brakes tend to be found on larger firearms, such as magnum rifles and artillery. A well designed muzzle brake can significantly reduce recoil, turning a rifle that would otherwise be punishing to shoot into a far more tolerable experience. A good example may be seen on the M82 Barrett sniper rifle. There are downsides to both recoil compensators and muzzle brakes. They direct more of the muzzle flash to the sides