Anti-Japanese War, weapons designer at Fengtian Arsenal

After the deal for the flamethrower submachine gun was finalized, Li Qinwu felt relieved. He immediately went to the finance department to pay the money, received the first batch of materials from the factory, and returned to the workshop to get the flamethrower submachine gun production line running at full capacity.

The workers in charge of the flamethrower submachine gun production line all came from the north. Li Qinwu told them that these guns were to support the northern soldiers in resisting the Japanese invaders. Now everyone was buffed and worked hard without regard for their lives.

They hoped to vent the pain of leaving their homes through work, and they also hoped that the soldiers in the north would kill the enemies with the weapons they made, giving them the opportunity to return home.

Seeing that everyone was very motivated, Li Qinwu walked around the workshop and chose to leave after confirming that there were no problems. He had more important things to do, the Sten submachine gun drawings.

Li Qinwu came to the newly opened weapons design department of Xiaoyi Arsenal. Compared with the weapons design department of Fengtian Arsenal, which had three three-story buildings and its own yard, the housing provided by Xiaoyi Arsenal was much more shabby.

Not to mention a yard, there is not even a building. There are only five small bungalows connected together. The paint on the walls has peeled off in some places. It looks like a warehouse that has just been cleared out. The sense of simplicity is overwhelming.

Fortunately, the bungalow was cleaned very well and had electricity. It was equipped with tables, chairs, benches, a design table and drawing tools.

He walked over to the drawing table, put a blueprint on it and clamped it, held a pencil in his hand, and began to think about the parts of the Sten submachine gun in his mind.

The Sten submachine gun has 47 parts and a very simple structure. Most of them are stamped. Only the bolt and barrel need to be processed by machine tools. No advanced technology is used as a whole.

This makes the gun very cheap, but it also comes with disadvantages such as low reliability, easy misfire, and poor quality.

Especially regarding accidental discharge, the safety feature of the Sten submachine gun is to pull the bolt over and lock it into the slot on the gun body. It is such a simple safety device.

When a soldier is on the move, the bolt can easily be caught by something like a branch or a backpack hook, causing the bolt to fall out of the slot and put the gun into a ready-to-fire state.

The Sten submachine gun was designed based on the fact that Britain was in a crisis of life and death and needed to be equipped with a large number of automatic weapons, so this unsafe weapon was manufactured. However, China is not facing such a serious crisis of national destruction for the time being. Li Qinwu feels that there is no need to copy this emergency product 100%. He can make some slight modifications on its basis to increase its reliability. Even if the cost increases, it will not increase much.

After deciding on the design direction, Li Qinwu began to write.

First of all, the buttstock. The original Sten submachine gun buttstock is just a simple metal stick. The advantage of this is that it is cheap and can greatly reduce the weight of the gun.

But the disadvantages are also very obvious. It is too easy to break and will bend with just a random hit. Moreover, the ergonomics is poor. The buttstock is just a metal stick, and the feel of using it cannot be compared with solid wood. It needs to be modified.

In China, an industrially backward place, wood is cheaper than metal. Removing the metal buttstock and replacing it with a wooden one can not only improve the feel, but also further reduce the cost!

Li Qinwu drew the data of the buttstock in a few strokes, thinking that since the buttstock had been modified, he might as well add a pistol grip.

The grip of the Sten submachine gun is a piece of metal connected to the buttstock. It looks awkward and feels terrible to hold.

We are not short of these two money now. At most, we can spend a dollar to make a pistol grip for each gun to improve the ergonomics of the gun.

Another thing is the magazine of the Sten submachine gun. Anyone who has watched one or two anti-Japanese dramas should have seen a scene where a soldier using the Sten submachine gun holds the magazine with his left hand.

It looks quite stable, and the magazine looks like it is meant to be held, however, this is the wrong way to hold it, which will cause the gun to feed poorly and cause fatal jams, which is very common in the hands of untrained recruits.

But in fact, this cannot be blamed on the recruits. The horizontal magazine is so suitable for holding. Anyone who sees it at first glance will think that the magazine is used for holding, and the correct way is to hold the short heat sink in front of the magazine.

This holding method is extremely awkward. The heat sink is very short and inconvenient to grasp, and it does not conform to the ergonomics of the human hand, so the recruits will subconsciously hold the magazine to shoot.

Li Qinwu had seen many old battlefield photos before, and it was clear that the soldiers of European and American countries often held their guns incorrectly during battle. If the Sten submachine guns were widely deployed in China, facing the less educated Chinese soldiers, the situation would only be worse.

The design of the Sten submachine gun is somewhat anti-human, and as a designer, Li Qinwu would not allow this to happen.

Moreover, the horizontal magazine of the Sten submachine gun is outdated. The horizontal magazine will make the center of gravity of the gun worse. Continuous shooting may cause the muzzle to swing left and right. This is also reflected in the Japanese Type 99 light machine gun.

At this time, people were still in the exploratory stage for the development of submachine guns, and had not yet realized that the use scenario of submachine guns was rapid assault and combat. Their awareness of the use of submachine guns was still stuck in the traditional infantry, lying on the ground and shooting at a distance, so they placed the magazine horizontally so that soldiers could crawl low on the ground and shoot.

But in fact, the correct positioning of a submachine gun should be rapid and mobile combat. The unstable center of gravity caused by the side shift of the magazine is very fatal. In fact, before and after World War II, most countries have realized this and the submachine gun magazines were moved downward. The submachine gun with a downward-moving magazine has a more stable center of gravity and the entire gun body is smoother.

Knowing the development direction of submachine guns, Li Qinwu naturally could not adopt the backward side-moving magazine layout. He planned to change the magazine to move downward in the Sten submachine gun he produced.

Of course, after the magazine moves down, the soldiers will subconsciously hold the magazine. After all, this magazine looks like a vertical grip. Where else can they hold it if not here?

This would also lead to poor ammunition supply, and Li Qinwu's solution was to lengthen the magazine well.

Since holding the magazine will cause poor feeding, why not just hold the magazine well?

Li Qinwu felt like he was a real genius. By lengthening the magazine well, the submachine gun became like a gun with a built-in vertical grip, which increased the gun's performance.

The last issue that needs to be solved is the accidental firing problem. The accidental firing problem of the Sten submachine gun is caused by the crude safety system. Its safety system is to pull the bolt into place and jam it in a slot on the gun body. If it is hooked by any debris, the bolt may fall off the slot, putting the gun into the ready-to-fire state.

Li Qinwu could not accept this crude insurance model. After all, if the more educated European and American soldiers had so many accidental discharge accidents, then there would be even more accidental discharges among the Chinese soldiers who had a lower education level and used guns more crudely!

Li Qinwu must make improvements!

Speaking of safety improvements, he subconsciously thought of the large paddle safety on the AK47. The principle of this safety is very simple. When you slide the large paddle to the safety position, a metal structure inside the gun will jam the trigger and lock it, making it impossible to pull it out.

This thing is quite simple to manufacture, and can be solved by adding four or five small parts. However, adding this kind of safety requires major changes to the internal structure of the Sten submachine gun. Once the internal structure is changed, the external structure also needs to be changed.

A big reason why the Sten submachine gun is cheap is its simple appearance, which is just a cylindrical gun body. If so many internal changes were made, the cylindrical gun body would change and the production cost would increase a lot.

Li Qinwu would never touch the main structure of the gun, so the built-in trigger lock safety would not work.

Moreover, in order to keep the cheap attribute of this gun, the budget spent on safety cannot be too much. So how to solve the problem of accidental discharge?

Fortunately, Li Qinwu's genius idea was quite weird. He thought of a solution that could reduce the accidental discharge rate without changing the gun structure.

He planned to weld a movable round hook directly onto the gun body.

Isn't it that the bolt of the Sten submachine gun is easily hooked out of the slot and causes accidental discharge? Then make a circular hook next to the slot, pull the bolt up and put it in the slot, and then turn the circular hook over and circle it on the bolt. Wouldn't this reduce the chance of the bolt being caught by foreign objects?

A movable circle hook, welded, the cost of such a small thing is almost negligible.

Of course, this comes at a price. Using a circular hook to hold the bolt reduces the chance of accidental discharge, but when soldiers want to fire, they have to take one more step to release the safety. They need to first push the circular hook away, then release the bolt from the slot before they can fire.

The extra action of turning off the safety may sometimes cost a soldier's life, but as the saying goes, this is the only way Li Qinwu can think of to increase the reliability of the firearm under the premise of reducing costs.

To create a complicated safety structure, the trigger would have to be significantly modified, which was obviously not in line with the original intention of the Sten submachine gun to be low-cost. Therefore, he could only choose such a simple safety method.