Complex sentence: The delay time in boiling of liquid to gas can cause a problem during rapid fire known as shootdown, another side effect is the variable pressure of the gas, giving a variable foot-per-second of the projectile.
Split into simpler sentences: The delay time in boiling of liquid to gas can cause a problem during rapid fire known as shootdown. Another side effect is the variable pressure of the gas, giving a variable muzzle velocity to the projectile.