Chapter 142: Magic Cannon

“What!? Did it succeed all of a sudden?”

Eto exclaimed, looking at the dummy ball flying beautifully, his eyes widening.

“It’s a relief that it flew at least. It means the design concept isn’t wrong.” 

Isamu said with a relieved expression beside him.

“Now then, is the barrel okay?” 

Since they had no idea how much load the barrel could withstand, they had no choice but to keep shooting and checking for now.

As this was just a confirmation of whether this method was viable, the parameters for the explosive power and range were set quite low. It would be slightly weaker than low-power magic.

Also, since no heat was required for propulsion, the heat parameter was set to its minimum value. It was very convenient not to have to consider cooling or heat dissipation.

They could immediately touch and check with their bare hands after shooting.

“Yeah. It doesn’t seem to break just by firing once. Shall we fire a few more rounds?”

After checking thoroughly and finding no cracks or deformations, they proceeded to durability testing.

As they continued firing the second, third, and fourth shots smoothly, something happened when they fired the fourth shot.

Along with the usual “bonn” sound, there was a “whoosh” sound, and white smoke spewed from the bottom of the barrel.

Although the dummy ball flew, its distance was much shorter than before.

“Oops, it’s leaking after all…”

Isamu muttered almost as if he had expected it and calmly checked the situation.

Upon inspecting the bottom of the barrel, he found that part of the joint between the barrel and the bottom was cracked, and pressure was leaking from there.

For this prototype, a cylindrical metal part was joined with a disc-shaped part about two sizes larger in diameter than the cylinder. Then, the joint was reinforced with tape-like metal.

Since the method involved creating a mold and pouring melted metal into it, it was possible to mold the bottom as a single unit. However, doing so would be inefficient for mass production.

Since the molds were essentially disposable, molding them as a single unit would mean only one could be made with one mold.

Separating the bottom allowed them to make long cylindrical parts and cut them. Since making the mold was laborious and time-consuming, reducing the number of molds increased efficiency.

“Hmm, I thought I had glued it quite firmly, but it seems it can only withstand three shots.”

Touching his chin, Eto murmured.

“There’s no helping it. Maybe we should use Metal Leech for the joint. But it’s not a material that can be easily used for mass production.”

Isamu and Eto exchanged a glance and chuckled wryly.

“Well then, shall we try other materials?”

“Yes. It’s interesting to see how much it will change with differences in thickness and material.”

Having finished the initial verification, they proceeded to test the other three patterns in the same way.

The second one was made of iron but with half the thickness. Although the barrel itself did not deform, the joint cracked after the third shot.

The third and fourth ones were made of a higher-quality metal called black iron.

It was about 20% lighter and harder than iron, so it was used for high-end weapons and everyday items as a superior substitute for iron.

Although Isamu wasn’t knowledgeable about metals, it seemed to be a metal not found on Earth, just like magic silver Mithril.

The manufacturing method was the same, but the sturdy parts were thinner.

As for the results, the joint cracked as expected.

“Hmm, it seems that devising a more robust joining method is the right answer, but for now, should we use magic circles for anti-magic?”

“That’s not it. If we come up with a new joining method, it will be useful for making other things too. Let’s leave it to the blacksmiths for that.”

Seeing the bottleneck clearly, Isamu and Etto discussed countermeasures.

While devising a more robust joining method that could also lead to technological development, they decided to solve the issue with magic circles for the launcher.

Considering that even with reduced explosive power for testing purposes, it only lasted three shots, the current solution was to use magic circles to achieve satisfactory range.

“Normally, we would solve the issues with existing magic circles through materials and technology… It’s scary to compromise and rely on magic circles.” 

Zvar sighed, watching Isamu and the others choose the solution through trial and error.

“However, since all the experiments so far have failed… Eto, how long will it take to remake the thinner iron one?”

“We have the leftovers from cutting the iron barrel and bottom, so it’ll take about half a day to join them together. But are we going to use the anti-magic magic circles?”

“Yes. Since it’s a magic explosion, it can be attenuated with those circles.”

“In that case, we have another thinner iron barrel left. We made it first but discarded it because it seemed too thin. Shall we try using that one? It’s lighter and easier to use.”

“Wow!? That sounds great! Let’s try that first. It’s lighter and more convenient if it works.”

“Understood. Then, let’s go back and integrate it right away.”

“Let’s do it!!”

They made a prompt decision. It had become a tradition not only in the research institute but also in the Klaufeldt family, including the knights.

Since they were used to it, they boarded the carriage without hesitation and set off for home. Watching them, Zvar sighed, not knowing how many times it had been after their stay.

“…At least these guys won’t become enemies. There was a reason for forming factions.”

Back at the research institute, Isamu immediately began integrating the magic circles.

While Zvar, feeling a little tired, drank tea in the break room and petted Orihime on his lap.

It was the essence of being a capable woman not to forget this kind of care.

“To prevent it from being unable to fire if I write too much, I’ll write only up to a little above the bottom.”

“That’s right. Shall we make the startup circle a separate system?”

“Yes. Ultimately, consolidating them into one system for simultaneous startup is ideal, but we don’t have time, so for now, it will be a separate system.”

“Then, I’ll make the startup circle.”

“Thank you. I’ll integrate the functional circles.”

While Isamu and Willem worked separately, Isamu adjusted the output to prevent the explosion from decaying until it was ejected, drawing magic circles only near the bottom of the barrel.

“Ah, if we attenuate the downward explosion, the pressure will decrease, so should we increase the output of the explosion…? Hmm, I don’t know how much is needed, so I’ll add a magic power adjustment function just in case. It was originally planned for the finished product anyway.”

Muttering such things, he added a mechanism to adjust the power.

With the adjustment of the angle, you could adjust the distance to some extent, and in the case of using it on flat ground, you could adjust the distance by getting closer to or farther from the target.

However, in a castle siege where you would use it on top of a defensive wall, you could hardly move forward or backward, creating blind spots. This would be fatal in a defensive battle.

Therefore, he believed that a mechanism to adjust the power of the explosion was necessary.

“All right, is this good enough?”

Isamu, who had finished working after about two hours, stretched lightly.

Since he had drawn it with an emphasis on speed, it looked quite rough, but that was acceptable.

Carrying the completed prototype ver.2, the group returned to the training ground to resume the experiment at the rocky area they had created earlier.

“Here we go!”

With the power slightly increased, Isamu activated it.

With a “bonn” sound, the bottom of the barrel briefly glowed.

The dummy ball landed in a slightly shorter distance than before.

“As expected, the ejection force has decreased. And… let’s see about the barrel. Hmm, it seems both top and bottom are fine.”

After confirming with a post-shot inspection that there were no abnormalities, Isamu nodded slightly.

From there, it was just a repetition of monotonous work.

Adjust the output to achieve the same distance as before, and once adjusted, measure the durability with several shots.

Since there were no signs of breaking even after firing ten shots this time, they gradually increased the output.

Until the surroundings were enveloped in the sunset, the experiments continued, but finally, even the dummy ball flew outside the training ground, there was no sign of the barrel breaking.

“Yeah. It looks perfect, doesn’t it? We’ll tidy up the appearance later, but performance-wise, this should be fine.”

“The effect of the magic circles is outstanding indeed. Maybe we can extend the range a bit more.”

“Judging from the decrease in magic stone consumption on the magic defense side, it seems we can still go a bit further. But if we extend it any further, we’ll end up shooting into the forest from Klaufedamm.”

The three researchers rejoiced at the excellent results.

As Willem pointed out, the distance from one end of the training ground to the other and from Klaufendamm to the entrance of the forest were almost the same.

Even considering the headwind, if it was only to be used for defensive purposes, there was no need to extend the range much further.

“In terms of practicality for the time being, that’s correct. Let’s confirm the maximum range just in case, considering situations where it might be taken to the field or horizontal firing is necessary.”

Since it made a big difference whether it was used or not, they decided to determine the maximum performance later and ended the experiment for the day.

Thus, the grenade launcher, which had reached a provisional completion, was named the “Magic Cannon” and would soon be mass-produced as a defensive weapon for the capital.

By the way, up to this point, they had fired over a hundred shots. Since there weren’t as many dummy balls, they picked up the ones that flew away and reused them.

Just like the underclassmen in the baseball club who had to retrieve balls, there was a need for someone to do the task, which was mundane and required repeated back and forth trips.

Since nobody wanted to do it, it was left to the underclassmen as usual, and this time, several young knights who had lost a rock-paper-scissors game were drafted for the task. However, once again, Orihime showed off her impressive skills.

Orihime, who quickly got bored of the simple task, started playing by catching the balls flying towards her and flicking them away in mid-air.

The knights were delighted to see this. They joined in, catching the balls in mid-air and playing catch with the ones flicked away.

Eventually, Mizeroi and Tiramisu, unable to resist the sight of Orihime having fun, also joined in, making it a rewarding task.

“Are you still going at it!?”

At dinner that evening, Zvar was once again astonished.

It happened just after they finished dinner when Isamu reported that he had figured out the magic defense gate and the magic cannon.

“Tomorrow, I’m thinking of making some modifications to the research institute. I’m not sure how effective it will be, but I’m thinking of trying to enhance the soundproofing effect.”

“Oh, soundproofing?”

“Yes. Since it’s within the grounds of the mansion, I think it should be fine, but I’m wondering if we can prevent sound from leaking outside.”

“I see. Are you going to increase the thickness of the walls?”

“Yes, I think the thickness will increase. However, the goal isn’t to increase the thickness, but it will end up thicker as a result.”

“What do you mean?”

“Do you remember the insulation stones? I might have explained them before, but they’re stones with small bubbles inside. In my world, they’re materials with a property called porousness.”

Isamu began to explain the properties of insulation stones.

“Porous materials have several characteristics. The first and most notable is their insulation effect. This has already been proven in the new refrigerators, right?”

“Yeah.”

Selfers nodded.

“Another characteristic is their sound absorption effect. In other words, they absorb sound and make it smaller. By attaching insulation stones to the inner walls of the institute, we should be able to prevent sound from leaking out. As a bonus, the insulation effect will also increase, so I think the rooms will be warmer during this time of year.”

“Do insulation stones really have that effect?”

“We won’t know how effective they are until we try them out… I’m thinking of making insulation stones in various patterns and testing them.”

“Yeah, that sounds good. If it works, I’d like to introduce them to the main mansion and the knights’ quarters.”

“Hmm? Did I hear you say you’re going to ‘make’ insulation stones…?”

Zvar reacted to Isamu casual statement.

“Oh, I haven’t told His Excellency about the insulation stones yet… They’re magic tools made by Isamu.”

“What!? Is that also made with magic tools?”

“Yes. They can be made by specifying the arrangement and size of the bubbles. As long as the shape isn’t too complex, no processing is required, so they’re quite convenient, you know?”

“…Sigh. I’ve lived quite a long time, but these past two days have been the most surprising in my life.”

Zvar shook his head slightly at Selfers and Isamu’s words.

“Since we’ll be working on it while adjusting tomorrow, would you like to observe? I’ve heard His Excellency’s territory is colder than here. By seeing it firsthand and getting an idea, shall we start by installing it in His Excellency’s mansion?”

“Oh, you mentioned it had insulation effects… I see. Alright, I’d appreciate the opportunity to observe.”

“Then, from after breakfast tomorrow, please look after us.”

And thus, on Zvar’s third day of staying, it was decided that another surprise would be born.

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