The Model 1935 or “PG” (Peso a Gaz, gas-operated) rifle was developed during early 1930s by famous Italian company Societa Meccanica Ernesto Breda. Originally designed to fire standard Italian rifle ammunition of the period, the 6.5×52 Carcano round, in semi-automatic mode, it was later redesigned to fire somewhat more powerful 7×57 Mauser ammunition with select-fire capability. The 6.5mm semi-automatic version, according to some sources, was pressed into Italian service in limited numbers in around 1943-44. The 7mm select-fire version was developed under contract from Costa Rica, and about 400 automatic Breda PG rifles were produced for Costa Rican government. Breda M1935 PG rifles were somewhat heavy, of complicated design, and expensive to make. Historical importance of these rifles is that Costa-Rican Breda PG automatic rifles were probably the first weapons to incorporate burst limiting mechanisms, which, when engaged, automatically cut the bursts of automatic fire after just 4 rounds, in an apparent attempt to conserve ammunition.
Breda M1935 PG rifle is gas operated, using annual gas piston located close to the muzzle, inside a muzzle cup / gas cylinder. An action rod runs inside the wooden handguard to the right side of the action, connecting the piston with bolt carrier. Barrel locking is achieved by rising bolt, which has single locking lug at the top of its head. Bolt rides on inclined surface, machined to the front of the bolt carrier. Upon coming into the battery this surface forces the bolt up, and the locking lug on the bolt enters the opening in the top of the receiver, rigidly locking the barrel. After discharge gas piston forces the bolt carrier back, and its sloped surface causes the bolt to drop down and out of engagement with receiver, unlocking it and allowing for extraction / ejection / feeding cycle. Ammunition is fed from detachable box magazine with 20-round capacity. Rifle apparently was available in tow versions – semi-automatic only and select-fire. The latter could deliver single shots, 4-round bursts or full automatic fire with cyclic rate of about 600 rounds per minute. Breda M1935 PG rifle is fitted into the wooden stock, and has adjustable iron sights and provisions to mount a bayonet.