The main consideration for fixing the barrel is the effect of recoil. My solution to this problem is to work on the barrel slot.

The groove is made slightly deeper than the barrel and flush with the inner wall of the barrel. Then, iron bars are used to tighten and fix the parallel barrels in the groove.

Even with strong recoil, the groove flush with the inner wall of the barrel will stop it, and with the reinforcement of iron bars, this structure is sufficient to resist the impact of recoil.

Next, we need to make a sear to hold the rear barrel in place, so that it can both seal and move. For this sear, I used a piece of forged steel that I made earlier.

There is a deep groove between the sear and the barrel. Below the sear is a self-made spring device that functions like a spring. I will explain this material in detail later.

Above the sear is a wooden frame panel, which was chiseled out along with the slot. The overall structure is somewhat like the movable slot door of a sheep pen, and its function is to fix the sear in place so that it doesn't bounce off.

Two small circular holes were drilled in the center of the sear, which corresponded exactly to the center of the two gun barrels.

That is, the place where the 7-shaped hammer needs to strike the primer through these two small holes.

This gun sounds easy, but just processing these parts and adjusting them took me several days.

Finally, I must mention the important hammer system. My ram can only release the fire and does not have the power to strike the primer. Therefore, a high-strength elastic material similar to a spring is needed to store the power.

I definitely can't make springs for now. The process of making springs is more complicated than making high-carbon steel. It requires precise calculation of the proportions of various elements and complex processes.

Since the spring approach is blocked, I have to find another way. Solutions are found by people; with imagination, any material can be used.

This elastic material is crucial; it needs to be a material with good resilience and strong elastic potential energy to have enough force to drive the hammer to strike the primer.

I considered many options, and finally decided to use a composite method to make an artificial carbon fiber elastic board.

I can't get my hands on carbon fiber, but I do have bamboo fiber that's just as elastic.

Among bamboo fibers, the outermost bamboo strips have the best elasticity and toughness, and the older the bamboo, the greater the fiber density of the outer skin.

To fully utilize the elastic potential energy of bamboo strips, one piece is certainly not enough. Therefore, a composite method is needed to combine multiple bamboo strips to maximize the elastic potential energy.

When it comes to composites, adhesives are indispensable. To achieve a high-strength bonding effect, it is necessary to first formulate an ancient adhesive called "Wannianlao".

In ancient times, glue was generally divided into two types. One type was plant glue, which was mainly made of plants such as glutinous rice and raw lacquer. For example, glutinous rice paste was mixed with lime to build city walls.

Another type is animal glue, which is mainly made of fish bladders, cowhide, and animal horns and hooves. It is generally used by carpenters for bonding wood.

To achieve the highest bonding strength, animal glue and plant glue are mixed together to create an ultimate adhesive. This glue was developed for special bonding needs, and it is said that objects bonded together can last for thousands of years.

Ten thousand years might be an exaggeration, but judging from the completeness of the wooden artifacts unearthed in archaeological excavations, several thousand years is certainly not a problem.

I've dried and preserved some fish bladders, and for leather, I can only get some from jackal skins. As for plant glue, I plan to use pine resin instead.

I chopped up the fish maw and leather, soaked them until soft, then added water and boiled them until they became a thick, yellowish gelatinous substance.

To achieve the desired elasticity, animal glue is used as the primary material, supplemented by plant-based glue, with plant-based glue added in only one-quarter of the total amount.

The bamboo strips used are made by scraping the bamboo skin, which is about one finger wide, thin on both sides until it is translucent, and then drying them over a small fire.

The baked bamboo strips are evenly coated with hot glue and then glued together layer by layer to form a thickness of three to four millimeters.

Afterwards, you can use two wooden blocks to clamp the bamboo strips, and then press stones on the wooden blocks to make them firm. Let them air dry naturally.

The elastic mechanism of the sear is also made in this way, but it does not require much elasticity, so the bamboo strips cannot be made that thick. They can only be stacked to a thickness of one millimeter. If they are too thick, it will be very troublesome to operate.

Because these elastic materials need to be air-dried, they are made in advance before other parts are made. Now this composite material has been completely air-dried.

I removed the wooden blocks holding the bamboo strips down, and now the bamboo strips were firmly glued together. Thanks to the high proportion of animal glue, these glued bamboo strips still retained excellent flexibility.

I bent both ends of the bamboo strips and released them; the composite bamboo material immediately returned to its original shape. Its resilience is good; it seems it can definitely replace carbon fiber boards.

I also tried the thin bamboo strip material, which is only one millimeter thick, and found that its elasticity and resilience are quite good, making it a perfect replacement for small springs.

Cut two sections of this bamboo material to a suitable length, bend them and insert them into the slot under the sear. The bamboo strips can use their elasticity to support the sear and return it to the position of the barrel, thus sealing the barrel.

The remaining task is to insert two appropriately sized, 3mm thick bamboo composite materials into the back of the 7-shaped hammer with the beveled groove, so that the hammer's striking pin can be pressed against the small hole in the sear.

After adjusting the angle, take out the composite bamboo strip, apply hot glue, and insert it into the inclined groove to make it firmly bonded.

And that completes the making of a double-barreled shotgun.

Its operating principle is the same as that of a crossbow. By manually moving the 7-shaped firing pin backward, the hook in the mechanism presses against the blade to complete the firing.

The composite bamboo strip at the back deforms backward due to the pressure from the 7-shaped striking pin at the front, thus generating a forward-accumulating potential energy.

Pulling the trigger releases the 7-shaped firing pin, which is then propelled forward by a charged composite bamboo strip, striking a small hole in the sear to fire the gun.

Now I only have one last step left: to build the shotgun shells. I'd only ever dared to dream about them before; I never imagined I'd actually make them.

Shotgun shells are usually made of brass or plastic. But I don't have brass right now, though I do have gold, which is more malleable.

Since these structures are formed by stamping using the ductility of materials, I think that the ductility of gold can also be used to stamp out cartridge cases.

The only drawback of gold is that the cartridge cases made from it are heavier than those made from brass, making them less convenient to carry in large quantities.

But now I can't be picky anymore; having gold for bullet casings is already pretty good.

If my ancestors knew that I was so extravagant as to use gold for bullet casings, they would be so happy they'd crawl out of their graves to thank God.