In this case, Zhang Fan's primary target was of course on those relatively strong foundation building peak masters, although these splits were scattered in twenty directions, but Zhang Fan was still able to make up his mind to pursue and temporarily unfold twenty or thirty times the speed of sound with the help of the Qiankun shield space, or just catch up one by one in a few minutes or so, and kill them one by one with the transformation electric arrow. In the past, the master of the peak level of foundation building like a strong enemy, even if he is self-cultivation, he is probably only one in two or three hundred, and less than one in ten thousand, even if he is weak. There is no need to waste the Divine Thunder Cannon shells, and they can be killed directly from a distance of about three or four miles. In the course of the journey, at least twenty-five unlucky disciples of the Nine Grades of the Foundation were killed.

What made Zhang Fan a little disappointed was that he had solved so many masters, which was more than the high-level strength of the Luoyun Mountain Chamber of Commerce before, but the harvest was still only a low-grade spirit stone and some talisman seals that were not of much use to Zhang Fan at this time, and there were not even many low-level storage bags and spirit beast bags. This barren land on the western border of the Boundless Continent really lives up to its reputation. At the same time, it also made Zhang Fan have a good impression of the previous lord of the Luoyun Mountain Chamber of Commerce.

Zhang Fan, who was not reconciled, temporarily gave up the pursuit of other ordinary foundation building nine rank enemies, but carefully conducted a thorough investigation of the scattered evil dao main altar that had been bombed by the divine thunder cannon before, and there was a major benefit---- only three lower grade spirit stones were stored in a secret area about four miles from the ground. In this way: Zhang Fan obtained a total of six lower-grade spirit stones, as well as a total of six lower-grade spirit stones converted into fragments. Although it still seems to be a little insufficient in Zhang Fan's subconscious, it can be regarded as barely touching some urgent needs, at least it will not let the Gathering Spirit Grass in the Qiankun Shield be broken.

Subsequently, Zhang Fan, in line with the intention of always thinking about improving his combat effectiveness in order to cope with unforeseen needs and trying not to waste time under any circumstances, spent about a day and again came to the largest copper mine in the entire Luoyun Mountain system on an average of thousands of kilometers.

Copper resources are of little use to ordinary monks or martial arts people, and are more of a daily necessities for the folk economy, as well as some bronze statues and sculptures. Therefore, there are not even masters of the Transformation Realm in the big cities in this neighboring area, and there are not even many martial arts people in the high-level realm of the Inner Gate. However, in such a place, Zhang Fan unexpectedly discovered the aura of some foundation building peak masters hidden in the mine, and there were six people in total. Obviously: these people's intelligence is a little outdated, and they don't know about the series of major changes that happened before, thinking that this battle can be stable in the case of an ambush, but they didn't expect that Zhang Fan is no longer what it used to be.

Of course, Zhang Fan did not support the opponent in this kind of squatting pit in a specific place, because no one knew that there were any organs or backhands that he did not understand. Still killing chickens with a knife like a knife relying on the Qiankun shield directly into the seemingly ordinary mine cave, with the divine thunder cannon from the Qiankun shield bombardment again, the violent explosion once again engulfed the entire mountain, six divine thunder artillery shells totaling twenty or thirty thousand tons of equivalent thunderstorm precision attack, all the ambush was wiped out.

Subsequently, Zhang Fan continued to start mining in the mine with a unique technique, under the fierce and intensive sonic offensive bombardment, groups of mountain rocks were shattered, under the precise detection of Zhang Fan's spiritual power and the control of the transformation spiritual power, the internal qi continued to gather into the air from all directions, constantly melting and softening in the heat wave with thunder, especially those copper water with low tolerance melted first.

In line with the principle that the more the merrier, Zhang Fan and his party mined in this copper mining area for about ten days in a row, and used about three months of processing and smelting in the Qiankun shield during these ten days. In the beginning, there were many copper levels above four percent, and even a rare bonanza in the modern earth's mining regions seemed easier to mine and smelt than before. However, even with the large scale of the society in the Luoyun Mountains, the scale of these mining areas, on which the private economy depends to a large extent, is also relatively large, and the grade has become lower and lower to a large extent under the situation of Zhang Fan's continuous overdraft mining. It was only after a total of 30,000 tons, equivalent to about one billion taels of copper, that the copper mine was roughly abandoned.

In the next 20 days or so, Zhang Fan went to the other two copper mines as quickly as possible, and spent a lot of time to collect about 10,000 tons of copper. In the case of a total of 40,000 tons of copper, about a quarter of the total space mass of the entire Qiankun shield was used. During this period, the smelting and processing industry in Qiankun Shield took Zhang Fan about a quarter or so.

After a month of time outside the shield, the time inside the shield is close to half a year of busyness, and Zhang Fan's "family background" is not what it used to be. The remaining useless Divine Thunder Cannon was re-forged and turned into a Divine Thunder Cannon with a relatively small warhead and a more reasonable appearance, mainly aimed at the peak masters of foundation building and even the ninth grade of foundation building. The specifications are not the same, and they are more targeted. More than 1,000 combined guns capable of attacking tens of thousands of foundation building masters.

The newly introduced 40,000 tons of copper were made into 30 giant divine thunder cannons weighing about 1,300 tons. The only reason why it is determined to be this specification is to ensure that the Shenlei Cannon shells with a diameter of about one foot and a length of about three zhang can be safely launched from the exit of the Qiankun shield with a certain margin, and even a more reasonable ratio of projectiles to the launch system can probably reverse the weight of this specification. To a large extent, a limit for such weapons. In addition, with Zhang Fan's high-level martial arts cultivation at this time, when this specification of the Divine Thunder Cannon is used externally, it is also an upper limit that can ensure that eight to ten Divine Thunder Cannons with a cumulative weight of 10,000 tons can be operated at the same time without excessively affecting the mobility and flexibility.

In terms of Zhang Fan's existing spiritual power and strength, because the warhead that can ensure safety and condensation is limited, it can't exert the full power of such a large weight space divine thunder cannon for the time being, even if he uses such a specification of divine thunder cannon, at most he can only deal with the masters of Jindan seven or eight grades like before, but the upgrade potential is undoubtedly huge. When designing something, even if there are still some difficulties that have not been solved for the time being, Zhang Fan also thought of leaving a certain amount of redundant space when manufacturing.

"Now the biggest problem that affects the power effect of the Divine Thunder Cannon is actually the problem of air resistance after the initial velocity exceeds 100 times the speed of sound, when the initial speed reaches 100 times the speed of sound, even the quasi-Xuangang has some phenomena that are not good to control with spiritual power and even unstable... Thinking of this, Zhang Fan also began to conduct some virtual exercises in the illusion of the Qiankun Shield to see what methods could be used to solve this problem.

In the end, Zhang Fan found that one of the more reliable solutions was to use the spiritual power to transform the internal qi directly into the air to create a "vacuum channel" with a diameter of more than one foot, which matched the direction of the attack and was about two kilometers long. At the time of firing, cast a vacuum channel near the shell as fast as possible. If this is the case, it is no problem that the speed of the shells fired reaches 3,000 times the speed of sound and 1,000 kilometers per second. And it is obvious that the faster the speed, the more the requirements for mental power can be reduced.

As for why it can't be higher than 3,000 times the speed of sound? The limit specification that can be made under the condition that the copper cannon body maintains a certain stability is about 1,000 times the original power.

Roughly calculated, if it can really be done, it will increase its combat effectiveness and even the opponent it can deal with by five grades, and if it encounters a Jindan peak master who converts the thirteenth grade of Jindan, it may also be possible to deal with it. If his own spiritual power cultivation is improved a little more in the future, it seems that the intensive offensive launched with the giant divine thunder cannon may not be impossible to deal with the opponent in the early Yuan Infant?

It was only after a little rehearsal of the opponent who came out of the copper in the Qiankun Shield that Zhang Fan began to realize that this would not work. A strong man of that level has an extremely strong attack range and even his own mobility ability, and the effective range of two kilometers is simply not enough to ensure his own safety. According to the calculations in the Qiankun Shield, a strong enemy of that level still has a relatively fragile cultivation in the high-level realm of the Heavenly People, and to ensure his safety, he needs at least an effective range of about fifty kilometers to be safe, which is also roughly a limit for his own perception of this kind of strong person: the premise is that people do not bring magic weapons such as illusion and stealth. Even if it is only theoretically calculated, to deal with a peak genius powerhouse of the Martial Dao Jindan of the Refining Nature Nature, it is necessary to have a safe distance of about two and a half kilometers to three kilometers. So at this time, this so-called powerful attack power is only "theoretical", and it may be useful when breaking through some special formations?

Zhang Fan, who felt some problems, of course, also thought of some solutions: according to his own understanding, there are two kinds of rune seals, one is the inner gate rune seal, which penetrates into the Qi Sea or the Mud Pill Palace to attack. It is also an offensive talisman that I often encounter. And there is another, which is essentially a reprint of some kind of spell. That is to say, a certain spell is stored in the form of a sigil and released under certain conditions. If this is the case, then maybe I can think of a solution from the aspect of the seal? If we can solve the problem of air resistance, plus we have a certain "guided" attack capability. Maybe the potential of this kind of means can be fully developed, and let yourself have the ability to leapfrog beyond the entire realm that many fantasy overhead protagonists don't have?

When he thought of this, Zhang Fan also felt that he couldn't go on like this. The essence of "scientific and technological activities" lies in "communication". Roughly calculated, if those people in Luoyun Mountain were really hiding before. For such a long time, there should be someone showing their heads, right? Could it be that when this kind of thing happens, there is really no one who will spend more than a month listening to the news in a key position?

After Zhang Fan came out of the Qiankun Shield in the mining area, he still thought about the impact that some of his previous actions might have on the mortal world. Just like in modern times, it is rare to throw away plastic bags, even if it is not beautiful in your hand, you have to find a garbage bin and throw it away. Zhang Fan didn't want to lose his morality, so he spent some more time looking for some gold mines, collecting wealth, and making up for the economic losses of the cities near the copper mining area before starting the journey to find the old man.