When studying the circuit PPSh-41 The absence of a return spring on the bolt is immediately noticeable, which is a key feature of Shpagin’s design. Unlike many foreign analogues of that time, here the return mechanism is located inside the hollow fire control handle, connecting to the bolt through a special rod. This engineering solution made it possible to significantly reduce the length of the assembled weapon and simplify its maintenance in the field, although it required the introduction of additional parts to transmit force.
Submachine gun design Shpagin submachine gun is based on the operating principle of automatic blowback, where the barrel bore is locked due to the mass of moving parts and inertia. Shooting is carried out from the rear sear, which means that the bolt is in the rearmost position before firing. When you press the trigger, the bolt is released from cocking, moves forward, sends a cartridge from the magazine into the chamber and pierces the primer with a striker mounted in a stationary barrel.
⚠️ Attention: The free shutter principle imposes restrictions on the power of the cartridge used. The use of cartridges with a more powerful charge in weapons of this design can lead to destruction of the bolt group and injury to the shooter.
General layout and main components of the PPSh
Structurally, the weapon consists of several main components, each of which performs a strictly defined function in the firing cycle. The basis is the receiver, made of stamped steel, which radically distinguishes PPSh-41 from milled analogues and made it possible to establish mass production at non-core factories. The shutter, which is the central element of the automation, moves inside the box.
The receiver is connected to the barrel casing, which also serves as a handle for holding the weapon with the left hand. The casing has a number of holes to cool the barrel during intense shooting, which is critical for maintaining combat accuracy. At the back of the box there is a locking mechanism and a trigger mechanism that provides single and automatic fire.
To quickly disassemble the PPSh, no tools other than a cleaning rod are required, which was a critical requirement of the technical specifications for the troops.
Automation mechanism: free shutter operation
Automation operating principle PPSh is based on the use of the energy of powder gases pushing a bullet along the barrel. After the shot, the bullet leaves the barrel, and the gas pressure continues to act on the bottom of the cartridge case, pushing it back along with the bolt. Since there is no locking of the barrel as such (except for inertia), the bolt begins to move backward immediately after the bullet begins to move, but advances it only after the bullet leaves the muzzle.
On the way back, the bolt compresses the return spring located in the handle and cocks the hammer. Having reached the rearmost position, the shutter stops and is fixed with a sear if the translator is set to single fire, or immediately goes forward if the automatic firing mode is turned on. The weight of the bolt is selected in such a way that its recoil is slow enough for the bullet to exit safely, but fast enough to ensure a high rate of fire.
⚠️ Attention: A high rate of fire (about 1000 rounds per minute) leads to rapid overheating of the barrel and accelerated wear of the chamber.
Trigger mechanism and fire modes
Trigger mechanism (trigger mechanism) PPSh-41 mounted in a separate housing and allows the fire mode translator to block the movement of the shutter in various positions. The design of the trigger ensures safe handling of weapons and the ability to select a firing mode depending on the combat mission. The mode switch is located inside the trigger guard, which eliminates accidental switching, but requires removing your hand from the handle to change modes.
In the “O” position (single fire), the sear locks the bolt in the rear position after each shot. To fire the next shot, you must release the trigger and press it again. In the "A" (automatic fire) position, the sear does not interact with the bolt as long as the trigger is held in the rear position, providing a continuous reload cycle.
Power system: magazines and disk boxes
Cartridges are fed from box magazines with a capacity of 35 rounds or disk magazines (drums) with a capacity of 71 rounds. The disk magazine, often called a “drum,” was copied from a Finnish analog and allowed long-term shooting without reloading, but had a number of disadvantages, such as the complexity of the equipment and heavy weight. Box magazines appeared later and became the mainstay of supply due to their reliability and compactness.
The cartridge is fed into the chamber by the movement of the bolt, which, with its lug lug, sends the cartridge pushed out by the magazine spring. The neck of the magazine in the PPSh has a bevel, which makes it easier to insert the magazine and remove the weapon from a holster or pouch.
| Characteristics | Store (box) | Magazine (drum) |
| :--- | :--- | :--- |
| Capacity | 35 rounds | 71 rounds |
| Weight (without ammo) | ~0.35 kg | ~1.45 kg |
| Dimensions | Compact | Bulky |
| Recharge speed | High | Low |
| Feed reliability | High | Medium (required forced scrolling) |
Barrel design and muzzle brake-compensator
Trunk PPSh-41 It is a non-removable element (in early versions) or conditionally removable (in later versions), pressed into the receiver. The bore has four right-hand rifling, providing the bullet with rotational motion to stabilize it in flight. To protect against burns and for ease of holding, the barrel is placed in a perforated casing, which also serves to attach the front sight.
One of the hallmarks of the design is the muzzle brake-compensator located on the muzzle of the barrel. It is a bell that diverts part of the powder gases upward, pressing the muzzle of the barrel down when fired. This allows you to compensate for the weapon's toss and significantly increase the accuracy of burst fire, which is especially important at a high rate of fire.
Technical details of the muzzle
The muzzle brake of the PPSh has a complex internal geometry, where gases escaping through the upper holes create a downward reaction force, counteracting the moment of force caused by the location of the axis of the barrel bore above the butt resting point on the shoulder.
Maintenance and care
To maintain PPSh-41 combat readiness requires regular cleaning and lubrication of the main components. Particular attention should be paid to the chamber and bore, where carbon deposits from the combustion of gunpowder accumulate. Cleaning is done with a cleaning rod using rags and solvents. The friction surfaces of the shutter, the return mechanism and the trigger parts are lubricated.
It is important to monitor the condition of the return spring, which is located in the handle. During long-term use or storage, the spring may lose its properties, which will lead to the bolt not moving to the forward position and, as a result, to delays in shooting. Regular checking of the integrity of the spring and rod is mandatory before each shooting session.
☑️ PCA inspection checklist
Frequently asked questions (FAQ)
Why does the PPSh have such a high rate of fire?
The high rate of fire (about 1000 rounds per minute) is due to the relatively small mass of the bolt and the short stroke of the moving parts. The designer deliberately did this in order to increase the density of fire at short distances, which was important for close combat tactics.
Is it possible to shoot a PPSh without a magazine?
Technically, the bolt can be cocked and fired by placing a cartridge directly into the chamber, but this is an abnormal operation. The automatic operation of the weapon is tied to feeding the next cartridge from the magazine, so without a magazine the weapon turns into a single-shot weapon and requires manual reloading after each shot.
What is the difference between PPSh-41 and PPD-40?
The main difference lies in the production technology. PPD-40 was made mainly by milling from solid blanks, which was time-consuming and expensive. PPSh-41 became the first Soviet submachine gun to widely use stamping and welding, which made it possible to produce weapons in huge quantities.
How does the muzzle brake work on PPSh?
The muzzle brake-compensator diverts part of the powder gases upward through special windows. The reactive force of this gas flow presses down on the muzzle of the barrel, compensating for the toss of the weapon when fired and improving the accuracy of the battle in bursts.
What caliber is used in PPSh?
The weapon uses the 7.62x25 mm TT cartridge. This cartridge had high penetration power and excellent ballistics at short and medium ranges, making it ideal for submachine guns of the period.