The casting produced by this method is slightly rougher than that produced by the lost-wax method, but who cares about the roughness of a grenade? It's not something to be played with.
To put it bluntly, they're all disposable items; as long as they can explode and have a high power, that's enough.
The casting process is divided into five parts.
- Molding: Using materials such as clay to create a model of an object, sculpting various explosion-shaped dividing lines. To put it more vividly, it's about making it into a pineapple-like pattern of stripes, then air-drying it before firing it to create the master mold.
The purpose of the dividing line is to evenly divide the grenade into countless high-speed fragments when it explodes, and these high-speed fragments are the key to its lethality.
- Mold making: Based on the master mold, clay is applied to the outside of the model to remove the outer mold used to form the outline of the casting. The mold is then divided into several pieces for demolding. At the same time, an inner mold made of clay is created that corresponds to the inner cavity of the container.
- Mold assembly: Combining the clay molds that have been air-dried and fired to form a cavity, with the gap between them being the thickness of the object to be cast.
- Casting: Molten metal is poured into a mold cavity. After the molten metal cools and solidifies, a blank for the grenade shell is formed.
- Polishing and finishing: Remove impurities such as burrs and dirt from the surface of the grenade casing. Then, simply polish and finish the interior of the object to make its surface smooth and regular, presenting its final form.
This seemingly unremarkable grenade casing actually took me two whole days to make. After several failed attempts at molding, I learned from my mistakes and finally succeeded in making the casing.
The next step is to wrap a layer of iron shot with thinned tree bark and attach it tightly to the inner wall of the cartridge case. Then, a cast iron detonator is placed in the very center.
The detonator's shape is somewhat similar to the firecrackers used during Chinese New Year, and it also has a time-delay fuse at the end.
Next, the clay powder that had absorbed nitroglycerin was gradually filled into the gaps. One reason for adding the clay powder was to secure the detonator inside.
More importantly, the content of nitroglycerin can be precisely controlled, and the porous nature of clay can reduce the sensitivity of nitroglycerin to impact, thereby greatly enhancing the safety of transportation.
After all, we're dealing with firearms, specifically highly explosive nitroglycerin, so we need to be very careful with safety measures.
The rest is much easier. I still plan to use an advanced firing pin structure for the grenade's triggering mechanism.
This method is currently the most mainstream triggering structure on the market, with a high triggering rate and low failure rate.
I still used composite bamboo skin to replace the internal energy storage spring. There is a closed iron cap at the top of the fuse, inside which is high-nitrogen, explosive nitrocellulose.
If you pull the safety latch on the grenade, the internal mechanism will be triggered and pop open the moment the grenade is thrown.
The force accumulated by the bamboo strips will directly strike the iron cap, causing a miniature explosion that ignites the time-delay fuse. Ten seconds later, the detonator is detonated, which in turn detonates the entire projectile.
The only drawback of this grenade is that the bamboo strip protrudes outwards, unlike the smaller spring-loaded type. However, it's not a big problem to hang a few pieces on leather items.
It would be a joke to say I wasn't nervous during the testing phase. This was the first time I'd ever manufactured such grenades in the real world, and it was the steel ball grenade with the largest area of effect.
The moment the grenade explodes, each iron pellet transforms into a projectile that shoots wildly in all directions.
If not handled properly, one could find themselves within the blast radius of the explosion's debris.
To ensure the safety of the experiment, I specifically chose a vacant wasteland as the test site.
The testing site was also carefully designed. First, there was a trench that could accommodate one person, which ensured my safety.
Secondly, there is a target made of leather that has been soaked and softened, and it is about the height of a person.
These targets are made to human proportions, and some are placed at different locations every ten meters.
The explosion data from the test will be directly applied to these leather targets, providing a direct understanding of the grenade's kill radius, projectile flight distance, and penetration power.
With everything prepared, I stood in the trench, my fingers already pulling the safety pin on the grenade. Now I threw it with all my might towards the area with the leather targets in the distance.
"Ten...nine...eight...seven..."
"boom!"
I silently counted the delay time of the grenade fuse in my mind. The moment I counted to one, a sound like thunder exploded fifteen meters away.
At that moment, I could feel countless whistling sounds rushing towards me, and I knew what those whooshing sounds were without even realizing it.
This time, I deliberately threw the grenade closer to see how much damage it would cause within a 15-meter radius.
The violent gust of wind generated by the explosion came and went quickly. In just a few breaths, everything on the ground returned to calm.
I dusted myself off and crawled out of the trench.
What I saw next was a horrific scene. Within a three-meter radius of fifteen meters, the leather handkerchiefs had been blown to bits.
Finally, I found one of them about 20 meters away. It had been torn into pieces by the high-density metal jet and was no longer recognizable.
Even the leather targets closest to me, furthest from the grenade, were not spared.
Although it wasn't blown beyond recognition like the leather targets in the center of the grenade, it still had six to ten holes pierced by the iron pellets.
If this damage were inflicted on a person, they would certainly be dead beyond any hope of survival.
I continued to look at the leather target at a greater distance, and even at a distance of twenty meters, there were still two or three holes pierced by iron pellets.
It wasn't until I had walked twenty-five meters that I noticed there were no more holes in the leather targets on this side.
I can now conclude that, with the current amount of nitroglycerin, the blast radius is between 15 and 20 meters, with the optimal blast radius being within 15 meters.
I'm quite satisfied with the results. With the arm strength of most people in the tribe, throwing a grenade more than 20 meters away is no problem. This grenade is just right for us to use for long-distance throwing.
However, for close-range use, you'll need to find suitable cover. The wilderness is full of cover; just find a large rock to hide behind, and you'll be fine.
Some details of the hand grenade still need to be improved.
For example, adding colored smoke to the delayed fuse to indicate the grenade's location can help teammates better judge the grenade's landing point and find suitable cover.
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