How did the Model 1929 six-inch gun fire so quickly?

How did the Italian Model 1929 six-inch mounting achieve its high rate of fire?

Electric training, elevation, hoists, and rammers, plus loading at any angle up to 45 degrees and efficient ammunition handling, made it nearly twice as fast as the Model 1926.

The Ansaldo Model 1926 and OTO Melara Model 1929 used the same nominal calibre, but their components were not readily interchangeable. Electric training, elevation, hoists, and rammers reduced manual handling, while the guns shared a common cradle. The Model 1929 could load at any angle up to 45 degrees, whereas the Model 1926 loaded only around 20 degrees, giving the newer system nearly twice the ammunition-handling rate. Muzzle velocity fell from about 1,000 to 850 metres per second and shell weight from 50 to 47.5 kilograms in attempts to reduce dispersion. Those changes did not fully solve the close-set guns' accuracy problems.