After returning yesterday, Qin Chuan went to the musket factory once, but because he was busy with the funeral and arranging the prisoners, he didn't stay for long, and only took a cursory look at the drill machine and the barrel.

At that time, the barrel had already been drilled out of the caliber, and the inner chamber was being scraped with a long square file, and the thickness of the pipe wall was ground to the same level.

Before he had time to go to the gun factory, Li Xuejing brought the finished barrel over.

Qin Chuan hurriedly got up and greeted him, and the other people present stood up one after another and surrounded him.

"Steward, please see."

Li Xuejing handed the barrel to Qin Chuan.

Qin Chuan took it in his hand and looked at it carefully, and then carefully checked the inner chamber against the light.

The barrel is exactly a meter long, the outside is made octagonal, and it is polished with a file, and the inner wall lines are straight and smooth, and everything looks perfect.

After looking at it carefully for a long time and not finding the slightest flaw, Qin Chuan handed the barrel to Chen Zhan, and then asked Li Xuejing, "How long did it take to drill the pipe?" ”

"On the 22nd, it was about ten days less than the time it took for the students to make guns with Sun Da in Donglai."

"Not bad."

Qin Chuan nodded, in this era, twenty-two is indeed fast.

"Steward, the students think that the drill bit and bearing workpiece still need to be tried with different heat treatment temperatures and durations, and if you can make finer bearings, sharper and tougher drill bits, the time taken to drill the bore can be greatly reduced."

"It's a matter of trying to figure out how to make a good tool, and by the way, has this barrel ever broken the drill bit?"

"Yes, one is broken."

"Well, the focus is on drill bit steel and heat treatment."

At this time, Chen Zhan handed the barrel to others and couldn't wait to say, "Big steward, let's go test the gun." ”

"Okay, let's try the gun, by the way, we have to open the screw mouth and drill the fire door."

"The big steward, the screw has been opened, just open the screw at the back door, and then drill the fire door."

"Okay, let's go drill."

Including Luo Daniu, Liu Youzhu and others, everyone couldn't wait, when they flocked to the musket factory.

Li Xuejing and a skilled craftsman drilled the fire door one time, and the other opened the screw opening for the back door of the barrel, and then turned the screws that had been opened in advance into the back door.

Half an hour later, the group went out with the barrel of the freshly made gun and went straight to the improvised shooting range that Zhao Mancai had made before.

Zhao Mancai had already heard the news and rushed over, bringing his freshly baked black powder, and reminding Qin Chuan heartily that he should not put too much, just one penny.

Li Xuejing and Chen Zhan fixed the barrel of the gun to a wooden board and loaded the three-coin black powder from the muzzle.

The reason why it is three coins instead of one money is because the barrel needs to be tested with a large dose of gunpowder, and the barrel is not cracked to be considered qualified.

Then Li Xuejing took out another lead and a strip.

Just as he was about to reload, Qin Chuan suddenly remembered something and hurriedly shouted "Slow".

Li Xuejing raised his head and looked at him suspiciously.

Qin Chuan stepped forward quickly, compared the lead bullet with the muzzle, and said: "Grind this lead bullet a little bit, just as big as the chamber of the gun, and then go get some tung oil and a palm-sized piece of skin, the thinner the better, go quickly." ”

Although others didn't know why, they still did as he said.

Soon, the lead bullet was sharpened to the exact same diameter as the chamber of the gun, and tung oil and a thin sheepskin were also obtained.

Qin Chuan used a file to grind the skin a little thinner, then cut off the size of his thumb, soaked it in tung oil, wrapped half of the lead, stuffed it into the muzzle, and then handed it to Li Xuejing, saying, "Poke it in, compact." ”

Li Xuejing took the tong strip and used a bucket hard, and the lead was passed to the bottom of the gun chamber at once.

"The big steward, the reload is much lighter and faster than before."

Qin Chuan said with a smile: "In the past, the lead was made larger than the gun chamber, in order to increase the air tightness, effectively use the power of gunpowder, and ensure the killing and accuracy of the lead, but the large lead is difficult to poke into the gun chamber, and the loading speed will naturally be very slow." ”

"In my way, the leather has been coated with tung oil, and it is easy to poke the lead into it, and there is a layer of leather sealing, and the air tightness is better than the previous big lead, and the power will naturally not be bad."

Chen Zhan on the side listened carefully, and was amazed: "Wonderful, really wonderful, a piece of sheepskin, it is so wonderful." ”

"Come on, let's try the gun."

Qin Chuan asked, let Li Xuejing put the wooden board that fixed the barrel on the ground, let the gun head aim at the target twenty steps away, and then pour a little fine gunpowder into the fuse hole of the fire door, and use gunpowder outside the fire door to lead a fire path out, until the pit dug by Zhao Mancai.

"The big guy should stand far away first to prevent the barrel from exploding."

Qin Chuan waved his hand to let Luo Daniu and the others stand far away, while he jumped into the pit.

Chen Zhan also jumped in, and finally Li Xuejing, who used a fire sickle to ignite the gunpowder that was led to the edge of the earth pit after coming in.

The gunpowder burned rapidly towards the fire door of the barrel, and suddenly there was a "bang", the gunpowder in the chamber of the gun was ignited, a tongue of fire erupted from the shallow muzzle, and several wooden targets lined up twenty paces away made a series of crisp sounds.

"The big steward, I didn't blow it up."

Li Xuejing was the first to jump out of the dirt pit and ran towards the barrel of the gun excitedly.

Qin Chuan and Chen Zhan also followed, and the others hula hula.

Qin Chuan picked up the plank, carefully inspected the barrel a few times, and then nodded with satisfaction.

The barrel is not cracked, at least not visible to the naked eye, and there should be nothing wrong inside.

Then, Qin Chuan took everyone to check the target.

I saw that the first two planks about a finger thick had been pierced, and the lead was embedded in the third plank.

Li Xuejing exclaimed: "The power of the chief steward is much greater than the bird gun that the students built with Master Sun in Denglai. ”

"Well, the proportion of gunpowder is different, and the power is naturally different, and we add leather in front of the lead, which is more airtight, and the power will naturally be much greater."

"By the way, according to your estimate, if you put one penny and two cents of gunpowder, how many steps can this gun fire? How many steps can I take to break through my armor? ”

"The bird and lead made by the students in Denglai have been exhausted in a hundred steps, and now this one is ...... It should be no problem to hit one hundred and twenty steps, if you want to kill the enemy, you have to be at least within a hundred steps, if you want to hit accurately, it is estimated that you need sixty or seventy steps, as for armor breaking...... Thirty or forty steps to break leather armor or cotton armor is no problem, iron armor and inlaid iron cotton armor will be more difficult. ”

Hearing this, Qin Chuan frowned slightly.

You have to kill the enemy within a hundred steps, and you can only break the iron armor in twenty or thirty steps, which is still too close.

This should be almost the limit of a front-loading smoothbore gun, if you want to increase the range, you can only engage in a front-loading rifled gun and get a mini bullet.

If you use a front-loading rifled gun with a Mini bullet, the effective killing range of Shangrao can reach more than 200 steps, and you can shoot accurately at a hundred paces, not to mention armor piercing, and when the sharp bullet of the Mini bullet rotates at high speed, it should be no problem to penetrate the iron armor at a distance of 50 steps.

I definitely have to get this thing, but I can't get it for a while, so I can only slowly explore it.

……

This first barrel tried a total of three shots, and then I didn't dare to try again because the barrel was very hot.

Li Xuejing also carefully checked whether the inner chamber was worn, the barrel made of refined wrought iron was easy to wear, and the bird guns made by the Ordnance Bureau often cut corners, and the barrels of fifty or sixty rounds had to be scrapped, even if this barrel was carefully made by Li Xuejing, I am afraid that it would only be about 100 rounds, and it would also have to be scrapped.

After returning to Mengjiazhuang, Qin Chuan gave all the work that should be explained, and then plunged into the musket factory with Li Xuejing.

Now, the bolt parts have been made and sharpened with a file to a qualified large specification, Li Xuejing began to heat treat these bolts, bury them in a crucible filled with toner, put them in the fire to boil, and then pour them into a basin of water to quench them to obtain a hard and durable bolt.

When watching Li Xuejing do these steps, a thought suddenly flashed in Qin Chuan's mind: the barrel of the later generations must be heat-treated, annealed before rifling, and after the rifling is drawn, the inner chamber must be quenched to ensure that the barrel is hard inside and tough outside, and the inner wall must be hard and wear-resistant enough.

If he could also quench the bore, the barrel would definitely be more durable, and the chance of exploding the bore would be greatly reduced.

However, quenching can cause the metal to deform or even crack, and if you throw a red-hot barrel into the water, it will be 100% scrapped.

However, if the cooling part can be controlled and cooled evenly, the barrel can be fixed with a precision clamp......

Thinking about it, Qin Chuan suddenly slapped his thigh, called Li Xuejing and several craftsmen over, and told them to immediately build two things, one is a copper pipe, and an empty pipe is left in the middle for filling water, the length is a little longer than the barrel, and the diameter of the gun chamber is the same, so it can be easily stuffed into the barrel.

The other thing is two pieces of iron that wrap the barrel, and the inner wall is made into an octagonal shape of the barrel, so that the barrel can be clamped perfectly.

Quenching estimates will not work, and there is a high probability that it will lead to deformation of the barrel.

But he can try carburizing and nitriding.

Later generations of gun barrels were nitrided on the inner wall, which could increase the hardness and wear resistance of the inner wall.

The main process is to mix and stir toner, iron powder and powdered nails, hair, horns, etc., stuff them into the chamber of the gun, and bury them in the charcoal pile for carburizing and carburizing.

When this is done, the burning toner is knocked out of the chamber, the barrel is fixed with two pieces of iron sheet that have been pre-reded, and the copper tube that is also red-hot is inserted into the chamber, and the copper tube is filled with water.

In order to achieve the purpose of cooling the inner wall of the chamber slightly faster than the outer wall, to ensure the internal hardness and external toughness.

The barrel is then put back into the charcoal flame, which is tempered at a low temperature to keep the outer wall of the barrel firm enough.

Simply put, it is to apply the Rodman water cooling method to the barrel to create a barrel that is hard inside and tough outside, durable and not easy to explode.

After listening to Qin Chuan's explanation, Li Xuejing shook his head again and again, amazed, and then began to work.

Qin Chuan stayed in the musket factory all the time, waiting with anticrative anticipation for the workpiece he asked for in order to test his new technology.