The internal gate bipolar transistor (igbt) is the most efficient switch they have for this application. Electrolytic capacitors will be used. I don’t imply to know what the cause for poor efficiency is, but since you’ve sprung it on me, I would say that most efficiency is lost due to the air gap between the projectile and the external iron shield (which covers the coil) at the muzzle. So this would indicate that I believe the primary loss of efficiency has to do with overall reluctance of the em field.