Muzzle velocity design. In a side by side comparison with the .50 BMG, the titanium round "of any caliber" released almost 28 times the energy of the .50 BMG, with only a 27% mean loss in momentum. Energy, in most cases, is what is lethal to the target, not momentum. In conventional guns, muzzle velocity is determined by the quantity of the propellant (burn speed, expansion), the mass of the projectile, and the length of the barrel. A slower-burning propellant needs a longer barrel to burn completely, but can, on the other hand, use a heavier projectile. A faster-burning propellant may accelerate
Magnetic reconnection where formula_18 is the mass density of the plasma. Solving for the outflow velocity then gives where formula_20 is the Alfvén velocity. With the above relations, the dimensionless reconnection rate formula_21 can then be written in two forms, the first in terms of formula_22 using the result earlier derived from Ohm's law, the second in terms of formula_23 from the conservation of mass as Since the dimensionless Lundquist number formula_25 is given by the two different expressions of formula_21 are multiplied by each other and then square-rooted, giving a simple relation between the reconnection rate formula_21 and the Lundquist number