Hong Tao will definitely not be able to figure out the overall breech rifling technology, but the technique of manually rifling with a steel pipe is much easier. As long as you have a high-carbon steel tool with the right hardness, you can do this. In fact, Qizu and they have already engaged in this kind of test again, but because high-carbon steel is not easy to obtain, and the processing hardness cannot be achieved by surface carburizing alone, the progress is relatively slow. Once the rifling can be drawn by hand, Hong Tao will immediately get the rifled cannon. It's easy to make, and if you put this rifled steel tube into the barrel of a large-caliber Dahlgren gun, you're going to have a front-loading rifled gun. Or directly use this rifled steel pipe as a hollow mold, and cast it directly in the barrel, which is stronger and more reliable than stuffing it in the later stage.

Why develop a rifled gun, what are the benefits of it? That's a lot of good things. Compared with front-loading smoothbore guns, rifled guns have warhead shells and weigh heavier than ball-ball shells of the same caliber. Due to the limitation of rifling, the airtightness in the barrel is much higher than that of the smoothbore gun, so that the ****** used can be much less, the bore pressure is smaller, and the damage to the barrel is correspondingly reduced, and the barrel can be made thinner and thinner, reducing the overall weight of the gun.

Although the chamber pressure and muzzle velocity of the front-loading rifled gun are not very high, its shell has a good aerodynamic shape, low air resistance, and the high-speed rotation of the warhead also brings flight stability, so it will hit farther and more accurately than the smoothbore gun. In addition, a conical warhead is heavier than a spherical shell, and even without a charge, it is much stronger than a ball to pierce armor by shape alone. The heavy hull 135 smoothbore gun of the Jinhe could not penetrate at all from a distance of 400 meters, but if it was replaced by a rifled gun, one shot was estimated to be a big hole. Unless it's half thicker. Then the Golden River will not go out. The whole is a big lump of solid wood!

"This is the fifth one, and it is also the best one, and now the heating time and the speed of the water flow have not been mastered too finely, and although the first four are also good, the quality is not very stable." Qi Zu admired Hong Tao's genius idea again, and only now did he understand that cast iron was still divided into white and gray, not only in different colors. The mechanical properties are completely different, and the way they are transformed is so simple......

"Have you test-fired? The result? Hong Tao leaned his face to the mouth of the cannon barrel and looked in, it was indeed a good cannon, and the bore of the cannon was scraped by a boring knife, giving off a natural luster of metal, which was very smooth, like a mirror.

"I haven't tried this one, so I'm not waiting for you to preside over it personally!" Don't say that Qi Zu can't make sycophants, and when it's time to shoot, he is not better than anyone else.

"Hey, hey, hey...... Alright, come on. Let's start with the full charge! Hong Tao couldn't help but shoot the goods, and he laughed so much that he was out of tune. Commanding a group of workers to push the cannon to the test firing range.

Premier Hong ...... Fill it with a little less medicine, this time it's a bit evil, the first three guns were blown up with no more than ten full-charge tests, and the fourth one test shots were also blown up, do you say it's because the barrel is too long? I have calculated that with three-fifths of the amount of medicine, it can hit as far as the full charge of the copper cannon, and the same cannonball ......" Qi Zu and Hong Tao walked to the test firing range together behind the sports car, and told Hong Tao a bad news as they walked, the new product is perfect, but there is still an Achilles heel, it is easy to explode!

"Ahh This is not a good thing, I'll see ...... later" Hong Tao was easy to blow up when he heard it, and his heart was cold. Okay, Bai is happy for a long time, get a time bomb on the ship, those gunners are not playing with themselves!

Ever since a test range was carved out in the woods to the south, the animals here have suffered, and at some point a large iron ball will fall from the sky, and one of them will stick to their heads, accompanied by a frightening loud noise and acrid smoke, so there is nothing but insects in this woods. Today's big iron ball came again, and it collapsed endlessly, and it collapsed for a whole morning before it completely stopped, and this cannon barrel that was extremely close to perfection in Qi Zu's eyes exploded again.

No matter what technology is used to cast the iron cannon tube, once it is blown up, it will always be more terrifying than the copper cannon barrel, which is why the ancient people did not dare to completely replace the copper cannon for hundreds of years even after casting the iron cannon tube. The entire cast-iron cannon exploded, and a fist-wide crack ran from the tail to the muzzle, and if there were gunners around, those crumbling cast-iron fragments would have to kill them, and even if they couldn't die, they would have to be mutilated.

"Prime Minister, what do you think is wrong? Is it that cast iron can't cast cannons? Seeing that his masterpiece was scrapped again, Qi Zu's eyes were about to drip blood, and this helpless and unprovoked blow made him shake his concept of himself and Hong Tao, and began to fundamentally doubt everything, which was a precursor to despair.

"Uncle Qi, don't be sad, I think this is a good thing, it just reminds me, what is the double diameter of your cannons?" Hong Tao didn't despair, he was biting his lip and looking at the angel to ponder. He could see where the problem with this gun was, and there was a solution, but he couldn't remember the recipe that was very out of the way.

"Eighteen times...... Just experimenting, I think it can be cast longer, twenty times is absolutely fine! Qi Zu got into the horns, he felt that the larger the diameter of the cannon, the more powerful it became, so ******** wanted to forge a cannon with a large diameter, which became his only criterion for measuring whether a cannon was perfect or not.

"Eighteen times! That's why, the barrel is too long, the bore pressure is too high, and if you don't increase the thickness of the barrel, you will definitely not be able to withstand it. I knew that a brown powder slowed down the deflagration and was suitable for the ****** of this large-diameter gun, but I can't remember the recipe for it...... Forget it, I don't want to, let's let the ordnance factory try slowly. Uncle Qi, before the slow-burning ****** is manufactured, I'm afraid we can only make a cannon with a low magnification, you can try how many times the diameter is appropriate, and then fix it below this magnification. You can build a few special large-diameter heavy guns, but the thickness of the barrel must be increased, don't be afraid of heavy weight. I don't use it on the ship, but I'll take it to Cape Town in the second half of the year, and I'll have two batteries built there, and I need it. Knowing the ratio of the new iron cannon, Hong Tao determined the reason for the explosion. It's not that Qi Zu's craftsmanship is ineffective, it's not that there is a problem with the cast iron, and it's not that the casting process is wrong, the culprit is that the barrel is too long.

The work range of black powder is limited, and its efficacy plummets after a certain diameter is exceeded, and with the lengthening of the barrel, the chamber pressure will increase exponentially. There is no trick to solving this problem, there are only two ways. Either don't be afraid of increasing the weight and thicken the barrel, or use a brown gunpowder as ******. This brown fire medicine uses charcoal that burns not enough to replace the charcoal in the black fire medicine, and the ratio also changes, and the powder made is brown.

It has no other advantages, only one characteristic, that is, it deflagrates more slowly than black fire. This thing is not as fast as possible, if it is too fast, it will become explosive. For large-diameter guns, it is better to burn the ****** slowly, otherwise the shells have not yet been fired, and the pressure is all borne by the bore, which is easy to explode. It's a pity that Hong Tao can't remember the ratio of brown fire and medicine, this job has to be replaced by a test, try it little by little, when it can be tried Hong Tao is not clear, anyway, it is not needed at present.

In fact, at present, it is not possible to use a large-diameter cannon as a naval gun, because there is no opponent, and there is no need for technical suppression for the time being. Now the small double diameter naval guns are sufficient, and it is only necessary to gradually replace them with cast iron cannons, ensuring supply in quantity and improving in quality, which is already very remarkable. Even if there is an enemy with the same naval artillery, it will not be able to stand the fight against each other.

A battleship must have at least thirty cannons, right? Just imagine, after a naval battle, three battleships were sunk on each side, and ninety cannons were gone. What is the feeling of ninety cannons? Two hundred tons of copper! Is 200 tons of copper too much? The annual copper output of the Great Song Dynasty is close to 10,000 tons, and judging from the numbers alone, it seems that it is not much. But don't forget, the pass rate of casting copper cannons is less than 15 percent, and even if it is 15 percent, it will have to occupy more than 2,000 tons of copper. A country spends a fifth or more of its copper on casting cannons, and a skirmish naval battle is gone, who can stand it twice a year? And this kind of investment is not a one-time thing, this gap must be filled immediately, and the cannons must be cast again, otherwise it is useless to have warships alone.

Was the British Imperial Navy powerful? Their warships were also plagued by a serious shortage of artillery, and many of them had to unload their guns and store them for storage after returning to port, or simply transfer them to another warship to continue to use them at sea. Britain and France both tried to cast iron cannons because of insufficient copper production, which could be used, but it was not very safe, and if you wanted to be safe, you had to make it very heavy, and in the end, the cast iron cannons were not used on a large scale on ships, and they were all used as fixed shore guns on the batteries.

But there is no such problem in Jinhewan, I have the mature technology of casting iron cannons, and the pass rate is several times that of copper cannons, this loss is nothing at all, as long as the battleship is built, the naval guns can be installed immediately, and then the fleet is here again, and then fight!

Needless to say, three or four naval battles are fought a year, even once a year, how many years can a country that casts cannons in copper hold out? Don't mint coins and daily necessities for the country's copper, and use it all to make cannons. What is copper? Copper is money in this era! If you don't say that fighting a war is a money, this sentence is very true, whether in ancient times or in modern times, fighting a war is about money. If you enter a war of attrition, people are one thing, money can also keep up, and after a long time, it depends on who has the lowest cost and who wins. With the iron cannon in Jinhewan, the cost of fighting a war was immediately reduced several times, and this gap cannot be made up by people alone, as long as Hong Tao's brain is not pumped, any country that wants to fight a naval battle with Jinhewan has no possibility of victory.

(To be continued.) )