Late Yuan Dynasty: I am the true emperor

Chapter 537 The Type 52 Rifle's Design Finalization

The first round of accuracy and range tests passed with high standards. The new gun performed many times better than the previous flintlock gun, with significant improvements in both range and accuracy. Several soldiers who participated in the test were very fond of the new gun.

Next came the tests of rate of fire and power. Tao Guangyi even had a small clock brought in to keep track of the time. Several soldiers conducted a one-minute rate of fire test, and the results were not much better than the old gun, but they were still acceptable.

Previously equipped flintlock muskets, with one round pre-loaded, allowed most soldiers to fire around four shots, with three shots being the minimum. If a soldier couldn't fire three shots in a minute, it meant their training was insufficient, and four shots was the average. Top-notch marksmen with fast hands could generally fire five shots in a minute, and some exceptional individuals could fire six shots, with an average reload and firing time of 12 to 15 seconds.

The new gun used in this experiment had increased frictional resistance during loading due to its rifled barrel and Minié ammunition. In addition, the flint firing mechanism was changed to a percussion cap firing mechanism, and the soldiers were not yet proficient in operating the new gun.

Especially in the process of changing the percussion cap, more time was wasted than before. One soldier even dropped his small brass percussion cap, which was only the size of a red bean. It took him a lot of time to bend down and pick it up, resulting in him only firing two shots per minute.

The average score for everyone else was three to four shots, barely passing, but the sharpshooter Xu Lu achieved a score of five shots in one minute.

Seeing this, Lu Jin couldn't help but click his tongue in amazement and immediately asked, "Why are you faster than them?"

Xu Lu quickly stood at attention and replied, "Report, Your Majesty, because I changed the loading procedure, although the flintlock muskets used paper-packaged fixed cartridges before, when loading, you need to first bite open the gunpowder bag, pour a little priming powder into the powder pool of the flintlock mechanism, and then pour all the remaining gunpowder into the barrel."

"After the new muskets were fitted with percussion caps, it was no longer necessary to pour the priming powder into the breech first. The entire powder charge could be poured directly into the barrel. This allowed for a change in the loading procedure: first load the ammunition into the barrel, then replace the percussion cap, aim, and fire."

"Moreover, this has another advantage. If you install the percussion cap first and then stand the gun upright to load the ammunition, what if your legs or feet accidentally hit the hammer, causing an accidental discharge? Wouldn't that smash your head? But if you load the ammunition first and then change the percussion cap, this problem will not occur. So I think the loading procedure should be changed."

Upon hearing this, Lu Jin immediately praised, "You're right. It seems you're getting used to this new gun very quickly. You can continue practicing using it. If you discover any problems, or have any suggestions for improvement or usage, you can also bring them up to me. When the new guns are introduced, I'll make you an instructor."

"Yes, thank you for your guidance, Your Majesty!" Xu Lu was overjoyed. Although he tried to keep his 17-year-old face serious, he couldn't hide the joy in his eyes. After all, he was still a naive young man.

A rate of fire of three to four rounds per minute isn't very fast, but it's a new gun after all. With continued training and increased proficiency, four to five rounds per minute should be the average. Although it's not as high as the old gun, it's still acceptable.

Then the final experiment, testing power and penetrating force, began.

Anyone who has watched military-themed movies and TV series has probably seen soldiers digging trenches, building breastworks, piling up sandbags, or using whatever they can find as cover during field encounters, such as trees or village walls.

However, whether the breastwork sandbags can be used as cover, how thick they need to be to stop bullets, and at what distance a bullet can penetrate a tree trunk, etc., all require a lot of experiments to collect data, and that's what they're trying to do.

The group quickly began shooting experiments on different targets. First, they shot at pine boards three to five centimeters thick at different distances to simulate common house gates and see if they could penetrate them. Next, they shot at a mud-brick wall common in rural areas.

As for the blue brick wall, forget about it. Even a regular blue brick wall that's two bricks thick can't be penetrated by a pure lead bullet, let alone a living tree trunk.

Round after round of firing, the results were as expected. Within fifty meters, the bullets could easily penetrate five-centimeter-thick pine planks. At one hundred meters, there was a chance of penetrating them. At one hundred and fifty meters, they could penetrate three-centimeter-thick planks, but they couldn't penetrate five-centimeter planks. The bullets would get stuck in the planks unless several shots hit the same spot in succession, but that was too difficult to do.

As for adobe walls, there is still a chance of penetration within 30 meters, but it is impossible to penetrate beyond 50 meters. However, this usually happens in rural street fighting, and the fighting distance is usually not too far.

Living tree trunks are the best cover material. Generally speaking, a tree trunk with a diameter at breast height of more than 20 centimeters is impenetrable to a percussion cap rifle at any distance. Of course, thinner trees may be penetrated, but no one would be foolish enough to use such a thin tree as cover, since it can't even cover one's body.
Finally, and most importantly, is the testing of armor-piercing performance.

Several people conducted shooting experiments at different distances on the Ming army's standard cloth armor, the Yuan army's lamellar armor, the general's fish scale armor, as well as cold-forged steel lamellar armor, quenched steel lamellar armor, and 2.5 mm thick forged plate armor.

The final results showed that within 100 meters, all armor except for the hardened steel lamellar armor was penetrated. At a distance of 150 meters, neither the cold-forged steel lamellar armor nor the hardened steel lamellar armor was penetrated, but both were dented and deformed to varying degrees.

When the distance reached 200 meters, even cloth armor became difficult to penetrate, while the Yuan army's ordinary iron lamellar armor, the Ming army's general's fish scale armor, and forged plate armor could still be easily pierced.

Beyond 250 meters, even fish-scale armor and iron lamellar armor became difficult to penetrate. However, forged plate armor remained utterly vulnerable. Lu Jin pondered, perhaps because the plate armor hadn't been quenched? Also, the shape of the plate armor—such a large, raised piece of wrought iron—might be better at protecting against slashing and blunt force trauma from maces than lamellar armor, but it's normal that it's not as effective as lamellar armor at protecting against punctures and musket fire.

Upon seeing the test results, Lu Jin frowned. The new gun did not have an overwhelming advantage over the previous flintlock gun in terms of armor-piercing performance, but at a distance of 150 meters, it could penetrate most common armor, which was actually quite good and an improvement over the previous flintlock gun.

In Europe, those countries wouldn't even set any armor-piercing targets, because in the original history, by the time Europe had widely adopted firearms, armor had already become obsolete. Since the enemy wasn't wearing armor anymore, why bother pursuing armor-piercing performance?
However, Lu Jin had to consider this, because in his era, the surrounding potential adversaries, whether it was Goryeo, the remnant Yuan Dynasty, Japan, Annam, or the Luchuan Dynasty in Burma, were all heavily equipped with armor. Therefore, when the Ming army was equipped with firearms, they had to take into account the armor-piercing performance of the bullets.

After completing the test, Li Dingbang was quite pleased. The flintlock musket he used before could only penetrate armor at a maximum of 100 meters, while the new musket extended its armor-piercing capability to 150 meters. This was a huge improvement, directly increasing the effective range by 1/2. What more could he ask for?

But when he turned around, he saw Lu Jin frowning, looking dissatisfied. So he immediately came over and asked, "Is Your Majesty dissatisfied with the armor-piercing performance of this new gun?"

“Hmm.” Lu Jin nodded. “The performance requirements for our weapons depend on the equipment of our hypothetical enemies around us. Right now, whether it’s the remnants of the Yuan Dynasty, Korea, Japan, Annam, or Luchuan in Burma, they are all heavily equipped with armor. So we need to have higher requirements for the armor-piercing performance of our muskets.”

"150 meters is a good armor-piercing distance for infantry. When the two armies are engaged in battle, if the enemy wants to rush over from 150 meters away to engage our army, this distance can be used to fire six volleys of three-stage volleys, which is enough to cause a lot of casualties to the enemy on the other side."

"But for cavalry, this armor-piercing range is not enough. If cavalry charges from 150 meters away, even with a three-stage volley, they can only fire three rounds at most. Each musket only has one chance to fire before the enemy cavalry charges over, and there is no time to reload."

"If we cannot inflict heavy casualties on the enemy cavalry during this one and only shooting opportunity, then our musketeers will begin to suffer casualties once the enemy cavalry gets close. Therefore, the armor-piercing distance should be as far as possible."

Upon hearing this, Li Dingbang frowned and immediately said, "To deal with armored cavalry, don't we still have hollow square formations and cannons? We should be able to hold them off, right?"

"Of course we can hold them off, but casualties on our side are inevitable. If we could improve the performance of our firearms a little more to reduce our casualty rate, that would be even better. We can't look down on ourselves; we have to hold ourselves to higher standards. Otherwise, how can we improve?"

Li Dingbang nodded, and was about to ask if there were any other options when Tao Guangyi immediately brought over a box and said, "Your Majesty, if we want to improve armor-piercing performance, I've also been testing two new types of ammunition in the workshop. They're a bit more expensive, but their armor-piercing performance is definitely better. Would you like to give them a try?"

"Oh? You've made steel-core bullets? Come and let me see them."

Tao Guangyi immediately opened the box and saw two kinds of paper-packaged bullets neatly arranged inside. One was wrapped in blue paper and the other in red paper. Apart from the bullets being a little longer, the red-paper-packaged ones were indistinguishable from the others.

Li Dingbang quickly asked, "What are steel-core bullets, and what are the differences between the two?"

Tao Guangyi immediately explained, "There are two main reasons why lead bullets cannot penetrate armor. First, the gunpowder is not powerful enough, so the bullet doesn't fly out with enough force, which is what Your Majesty refers to as initial velocity. Second, lead bullets are too soft to penetrate iron armor."

"So His Majesty proposed a method to pre-embed a smaller steel bullet when casting lead bullets. This way, when the bullet hits the target, the outer lead layer may soften and break, but the hard steel bullet inside can continue to penetrate the armor."

"Then we designed two new types of bullets based on this principle. The one wrapped in blue paper is based on ordinary lead bullets, but with an 8-millimeter diameter cast iron ball inside, the kind used in flintlock shotguns. It is made with existing materials and processes, so it is relatively inexpensive to manufacture."

"These bullets, wrapped in red paper, have elongated heads, each about 3 centimeters long, almost an inch. They also use more gunpowder. Inside the bullet is a quenched high-carbon steel core, 6 millimeters in diameter and 2 centimeters long, made using the carburizing process for machine tool cutting tools. It's quite expensive, but the hardness of the bullet core is undeniable. Moreover, the weight of the bullet and the amount of gunpowder have been increased, so its power should be quite impressive."

"That sounds reasonable. Would Your Majesty like to give it a try?"

"Then let's give it a try. Start by shooting at the 150-meter target. It's pointless to shoot at anything too close."

"Yes!"

So the armor-piercing experiment began again. After only a few shots, the results astonished everyone. These two types of bullets were indeed worth their price!

Iron bullets easily penetrated the strongest armor plating, including hardened steel armor, and cold-forged steel armor, up to 150 meters. They could still penetrate it at 200 meters. At 230 meters, the cast iron bullets were stopped by the hardened steel armor, but the cold-forged armor could still penetrate it. It wasn't until 250 meters that the cast iron bullets were stopped.

Another type of high-carbon steel quenched steel core bullet has even more insane power. No matter what kind of armor you wear, it can easily penetrate it within 300 meters. As long as you can hit it with your gun, there is no armor that it cannot penetrate. It's like stuffing a high-carbon steel drill bit into the bullet, leaving the group of people dumbfounded.
Lu Jin wasn't as surprised as they were, because he knew that steel cores were almost standard on ordinary rifle bullets in later generations, and those without steel cores were rare exceptions, so their armor-piercing performance was naturally beyond doubt.

The problem now is whether the Ming Dynasty has the financial resources to equip itself with steel-core bullets as ordinary lead bullets.

So Lu Jin immediately asked Tao Guangyi, "If we follow the design of this steel-core bullet and replace the steel core with an ordinary wrought iron soft steel core, without using the carburizing process, as long as we can guarantee an armor-piercing range of 200 meters, can we reduce the cost?"

"This," Tao Guangyi thought for a moment before saying, "We have a steel-making method. Although the success rate of steel-making is not high, mass production of wrought iron is still not a problem. The main problem is the processing of the iron core and the casting process, which are relatively labor-intensive. The production efficiency and labor costs are relatively high, and it is not easy to cut corners on this. Even if we cut out the carburizing process, the cost will definitely be at least twice that of lead bullets."

Lu Jin said, "You can't do the math like that. If you only consider the materials, lead is much more expensive than iron. If you add a wrought iron core to each bullet, how much lead material can you save? Isn't that much cheaper than the material cost of pure lead?"

“But the main costs of adding an iron core are machining and labor,” Tao Guangyi immediately reminded him.

"Then let's build an automated iron core manufacturing machine and an automated casting furnace. By saving on labor costs and machining fees, we can actually save on lead materials and reduce overall costs," Lu Jin immediately decided.

"Huh?! A casting furnace?" Tao Guangyi was taken aback and asked in surprise.

“That’s right. You think we don’t need a casting furnace if we don’t make bullets? Actually, even if we don’t make bullets, I still plan to cast movable lead type. You’ll still need to get the type casting furnace working. Casting type is casting, and casting bullets is casting. What’s the difference? It’s just a matter of changing the casting mold.” Lu Jin said, having already planned ahead.

"Casting lead movable type, that's something worth trying. It could be used for both military and civilian purposes. But what kind of machine would be used to make the missile core?"

"Of course it's an automatic nail-making machine. You insert the iron bar, it cuts it automatically, and cold-forges the nail head. With a little modification, it can be used to produce bullet cores. It only requires three actions and functions: feeding, cutting, and cold-forging. It's not difficult in mechanical design. You should understand, right?" Lu Jin immediately reminded him.

“This does sound easy, much simpler than those interconnected machines. We can give it a try,” Tao Guangyi nodded immediately.

"Then it's settled. The gun is definitely fine; it can be finalized directly and called the Type 4052 rifle, or Type 52 rifle for short. As for the bullets, it depends on your development progress. If you can get the iron-core bullets sorted out, then we'll go straight to mass production and standard equipment with iron-core bullets," Lu Jin immediately decided.

Li Dingbang then came over and reminded him, "Your Majesty, which type of bayonet should we choose? There are three types of bayonets available."

Lu Jin frowned and thought for a moment, then immediately asked the soldiers who were participating in the test, "Which one do you prefer?"

"I like this double-edged sword-shaped dagger. It looks like it has strong penetrating power and should be able to pierce through armor."

"Let's not go for it. I think a single-edged knife is more practical. It only has one edge and is cheaper."

"Moreover, each soldier is generally equipped with a short decapitation knife for cutting off heads. If a blade-shaped bayonet is chosen, there is no need to carry an extra decapitation knife, which can reduce the burden considerably."

Several soldiers immediately began to discuss, but no matter what they chose, none of them chose the barrel-mounted bayonet; they all chose the bayonet with a mortise and tenon joint. The only difference was whether they chose the sword-shaped or the knife-shaped bayonet.

Seeing this, Lu Jin thought for a moment before saying, "Then let's produce a small batch of both of them and send them to the military for trial use. We should also calculate the production efficiency and cost of the two bayonets and not finalize the design for now."

"Yes!"

(End of this chapter)