To cast, you must first solve the casting mold, sand mold manufacturing, sand mold centering, followed by the casting process, the hollow metal ball must be as thin as possible in the shell, the thinner the space, the larger the charge, the greater the power after the charge is blasted. If used as a shrapnel, it can be filled with iron pellets and explosives with a diameter of 20 to 8 mm.

Therefore, the hollow bullet is a thin-walled part, and it is a spherical thin-walled part, which is one of the most difficult thin-walled parts to cast.

Of course, it's easy to say, but it's another thing to do. With the current technology of various countries, the thickness of the cast hollow sphere is less than the thickness of a thumb, or even thicker, and the projectile below 20 catties has no room for charge blasting, so it can only be used for projectiles above 30 or 40 catties, and the effect is not ideal.

The wall thickness of the Xianjun hollow bullet is only six to seven millimeters, and it can also be made thinner, but thinner pig iron will be brittle, unless steel is used, but the fluidity of steel is poor and it is not suitable for molding, and the number of fragments is not as large as pig iron.

Solve the mold, sand mold, casting process, then the casting size, charge mode, if the use of shrapnel, because the projectile occupies the space in the shell, it is bound to reduce the explosive material, so it increases the difficulty of explosion fragmentation, and finally the selection of fuze and delay fuze arrangement.

Due to the dimensional accuracy of the sand mold and the thermal expansion and contraction of the metal, the external dimensions of the casting are not uniform, of course, if the projectile is made smaller, the casting accuracy error is large, and it can always be put in. But the result is obvious: a 100-millimeter caliber cannon equipped with a 90-millimeter spherical projectile can be fired, but the accuracy of the shot can be difficult to say.

With the current casting technology of various countries, castings below 100 catties can control the tolerance within plus or minus 1.5 millimeters, even if it is a very high level, and the precision casting of half a millimeter can not be counted on at all.

The reason is also very simple, the tolerance accuracy of castings below 100 catties in Yongxing City can only be controlled between plus or minus one millimeter, and it is almost impossible for other princes to surpass the technology of Xianguo.

For this reason, it is necessary to customize a large spherical rough grinding machine, which is specially used to grind projectiles with excessive size, grinding dozens of projectiles at a time, due to the small margin, a few minutes or even more than ten minutes can be completed on the machine, which is very convenient.

A series of processing problems have been solved, and if gunpowder can make use of black powder, the fuze is an unavoidable problem.

At present, no chemical system has been developed in various countries, so the choice of materials and structures of the fuse is very limited, either by rubbing black powder into a fuse, or by using grease and phosphate rock powder to make a starting rod, but either one, it can not solve the delay accuracy and blind fire well.

The hollow charge bomb of the Xianjun army was the first to use the safety fuse, the advantage is that it is easy to use and has a certain hardness, but the disadvantage is that it is easy to blow up and lose water, and it needs to be cut in advance, which is difficult to grasp.

Therefore, in recent years, the rod delay fuze has been developed, and the length of the fuse rod can be freely selected according to the target distance and projectile speed to determine the delay time, and then the projectile is inserted, which basically solves the disadvantages of blind fire and insufficient delay.

All the processes and technologies have been solved, and the last problem has to be solved, the orientation of the fuse. The projectile is round, and it will roll after being bore, so it is necessary to fix a circular hollow cork at the end of the fuze, and the fuze is aimed at the hollow place of the wooden support, when the gunpowder is ignited, the fuze is ignited together, the fuse is burned out, the projectile charge is detonated, and the projectile is exploded and sprayed, forming a barrage.

The whole process is simple to say, but to implement it in reality, a complete set of industrial systems and sufficient industrial population are needed. Of course, if you are only satisfied with making do and solving the problem of whether there is something or not, it is okay to make some shoddy products, but the problem is that with the current technology of various countries, I am afraid that it is difficult to even make shoddy products.

At this time, the guard camp fell into a sea of fire, the explosions were endless, Du Ruixun woke up and rushed out of the dormitory in shock, only to look east, the city has turned into a sea of fire, and there are constantly new explosions one after another, his eyes are almost blackened, and the blood in his chest is rolling and surging with anger, I just thought that it was a soldier who ignited the gunpowder and caused such a disaster.

"Wang Xie, Wang Xie!"

Du Ruixun shouted loudly, and the protector Wang Xie came in a hurry:

"General, the sky-shattering fire camps outside the south gate and the north gate also exploded, and the last general suspected that it was a sneak attack by the Xian army."

"The Xian army sneak attack!?" Du Ruixun was suspicious, and hurriedly said: "Why is the Xianjun army's sneak attack unaware, it can ignite the three large battalions of our army at the same time, quickly, prepare horses, follow me to see!" ”

"No!"

In the panic, Du Ruixun led people to the east gate with his armored horse, and the head of the east gate had been engulfed in flames, and there were fires burning inside and outside the city walls, even in the open space. At this moment, two explosions were heard in succession not far in front of him, followed by several more, and it was impossible to distinguish what was exploding.

At this time, when the sky was dark, Du Ruixun had no knowledge of advanced weapons, and he really couldn't see the cannonballs falling in the sky, only to see the fire inside and outside the city, his mood was already extremely bad, he said to the escort general Wang Xie in a deep voice:

"Go, I'll find the official and the general!"

"No!"

Du Ruixun was worried that the explosion at the head of the city would affect the city, he did not dare to approach the city wall of the east gate at all, dismounted and stayed in place to wait for Wang Xie to find people.

"The East Gate is the most official!"

Du Ruixun asked sharply, and Wang Xie hurriedly said:

"General Qiyu Du, Zuo Du Tong Quan was killed by the bombing. According to the report of the soldiers defending the city, three red lights were found in the sky on the opposite bank two moments ago, and when they were about to report it, the head of the city and the camp of our army outside the north and south of the city exploded at the same time, and at the same time, a large area of fire appeared on the river side of the opposite bank, like the traces of the Xianjun army's earth-shaking fire. ”

"What, the Xian army is shaking the sky and the fire is by the river!" Du Ruixun was taken aback, and hurriedly said: "Why is the Xianjun heaven-shaking fire so powerful. Let's go, go out of town with Ben to see! ”

"No!"

Du Ruixun did not know that Wei Guo was also working day and night to develop a hollow charge projectile, and it was likely to have failed, so the perception of artillery shells was still at the level of solid projectiles.

But Du Ruixun knew that the Overlord Cannon could be bombed with a medicine pack, so he immediately thought that the Xianjun had copied the Overlord Cannon, but he couldn't figure out how the Overlord Cannon could hit a distance of two or three miles, and what a huge volume it would be.

When the horse went out of the north gate, the camp ten miles away was also a sea of fire, arriving near the bank of the river, it can be seen that the opposite bank is ten miles apart from north to south, and there are three rows of fires faintly, and it is not clear in the telescope. The only thing that could be seen was that the three rows of flames were spraying flames at an extremely fast speed, and in the blink of an eye, explosions came from the west bank one after another, the speed was so fast and powerful that Du Ruixun was shocked.

At the same time, countless fires on the north and south wings of Pingliu County on the east bank quickly rushed to the shore, and Du Ruixun felt unprecedented fear and shock for the first time in his life.

"It's the Xianjun Army's sky-shaking fire, it must be the Xianjun Army's secret who created a newer sky-shaking fire! Too fast, too fast! ”

At this time, the protector Wang Xie said:

"General Du, our army should immediately counterattack."

Du Ruixun's face sank like water, and he said in despair:

"It's over, it's all over...... Our army's earth-shattering fires are all over......"

He had already realized that the sudden attack of the Xian army was intended to destroy the artillery of the guards, and without the artillery, it would not be possible to threaten the Xian army on the shore.

"Pass on my military order, the two battalions in the north and south outside the city will immediately retreat ten miles to the west. At the same time, he sent men and horses to all armies as soon as possible, urging them to beware of the salty army's earth-shaking fire. ”

"The last general obeys!"

Issuing a series of orders, Du Ruixun almost sat on the back of the horse, gasping, he knew very well that this battle was more auspicious, but what he didn't know was that this was the beginning.

Two quarters of an hour later, the artillery of the Fourth Town and the artillery of the armed battalion were in place, with 18 catties of guns, 20 catties of guns, 36 catties of cannons, and a number of 72 pounds of heavy guns, and in the deafening roar, the prelude to the first hot weapons war in the history of the Central Plains continent began.

A round of projectiles roared across the heads of the guards and soldiers, exploding countless iron pellets in the air, mercilessly devouring every living life, and the war crushed the body of the old era with its unprecedented situation, deeply marking the brand of an era.

Du Ruixun's retreat order eventually became the road to death, and the artillery fire of the Xian army chased the fleeing guard soldiers, and the Xu Jin barrage was like a cruel vicious dog, frantically tearing every life on the way to escape, almost effortlessly.

The tens of thousands of guards and soldiers who were originally deployed in the north and south camps of Jiangquan collapsed under the cover of the artillery of the Xian army, and they were killed and wounded, let alone ten miles of land, and even if they escaped from twenty miles of land, it would be useless.

Around four o'clock, the sky was slightly bright, and two hot air balloons were raised in the north and south of Pingliu County to observe the damage effect, and at this time, the guards also raised a hot air balloon to try to find out the situation of the Xian army.

Looking at the messy military camps in the north and south of the West Bank, Old Mooney couldn't help but feel a cold sweat down his spine, and he said in a daze:

"That's it!"

Bai Liyan was calm, put away the telescope in Mooney's hand and said:

"This is just the beginning, they are going to flee west, so all that awaits them along the way is cannonballs. If you want to survive, you have to continue to run south or north, but our artillery can turn around at any time, so if you want to survive, you have to jump into the river.

Your Excellency Mooney, you have also seen the strength of our army's artillery, there are only more than 300 guns here, and there are other armies, if necessary, this commander can be multiplied at any time, if your country still wants to be an enemy of our Central Plains, you might as well weigh it. ”

Mooney was overshadowed, he knew very well at this time that Bailiyan had given him a lot of face, and in the past, it was likely that he was the one on the other side.

Seeing that Mooney was silent for a long time, Bailiyan said again:

"The guards have fled westward in a rout, and there is no threat to the shore, how about your Excellency watch the artillery with Ben Shuai?"

Mooney was astonished when he heard this, and he hesitated:

"This ...... Is this okay! ”

"Yes, as long as it is conducive to the peaceful coexistence of the two countries, this marshal does not mind that Your Excellency will take away some secrets. Sometimes it is necessary to deepen the understanding. Let's go, go to the riverside and have a look. ”

At this time, Mooney's expression was complicated, and Bai Liyan was sure that the previous bombardment and the corpses on the other side had successfully deterred the greed and military adventure ambitions of the Jinxuedi people, at least now they would no longer think that the technological gap with the Central Plains was only a star and a half, but a world apart.