The Canon de 138 mm Modèle 1929 was a medium-calibre naval gun of the French Navy used during World War II.

They were initially installed within the mountings, but were moved to the outer sides of the turrets to free up room.

The shells and their powder charges were transferred to a tipping drum that was rotated to match the bearing angle of the guns and then loaded.

This problem, coupled with the "poor quality of manufacture of the guns, the unsatisfactory profile of the breech, resulted in a firing cycle of only 3–4 rounds per minute during the early trials with jams and failures frequent", rather than the planned 10 rounds per minute.

A further problem was that there were only two loaders assigned to the gun crew; they tired quickly during prolonged firing.

Some fixes were identified, notably modifications to the breech, installation of split loading trays and reinforcement of the catapult rammers, but they had to wait until the ships' next refit to be implemented.

[5] Five-round ready racks for each gun were added to the sides of the turrets during the refit to compensate for any problems with the loading systems.