 The strength of the system was that the barrel was exposed to the enemy for a minimal amount of time, and with naval guns of the time firing on a flat trajectory, it was virtually impossible for an enemy ship to drop a shell on the emplacement, with its sloping rock glacis in front.Disadvantages of the system included a slow rate of fire (perhaps one shot every two minutes), and a propensity for the complicated hydro-pneumatic system to leak.The 6-inch guns used "non-fixed ammunition", that is, the explosive cartridge that propelled the shell was stored and loaded separately from the shell or shot.