Chapter 21

The more Jeff, Jr. thought about it, the more he wondered if he was doing the right thing by trying to marry the new exploding bolt to the machine gun. Under the right circumstances, it could be a marriage made in heaven, but under the wrong circumstances, it could be a marriage made in hell!

The problem with using the explosive bolt in the machine gun was that high rate of fire. The very reason for the machine gun was to throw out as many bolts as possible in as short a time as possible, and that was exactly the opposite of what the explosive bolt was to be used for. The machine gun worked against a single ant or a mass of ants, but the explosive bolt was wasted against a single ant. Question: How many explosive bolts were supposed to be fired at a mass of ants? Answer: Just one bolt!

Therefore, using the explosive bolt on a machine gun was counter productive! He should look at the explosive bolt as ammunition for a weapon like an RPG. This was reloadable, but still basically a single shot weapon. Therefore, Jeff, Jr. realized that he should design a special crossbow to fire just one bolt per loading, but to fire it well. Ah, that was the answer, he wanted a crossbow version of an RPG tailored to the requirements of the Carboniferous era.

Jeff, Jr. backed off of the explosive warhead and dropped back to the design of the best, most powerful crossbow that he could reliably make. Forget everything else for the moment, just concentrate on that. Back to pencil and paper and doodling for a while. He came up with a device that might be too heavy to be carried around, but that was another problem to set aside for the moment.

The resulting crossbow used a bow made of spring bronze, something that was hard to make with their technology, but they could not yet make spring steel. Likewise, he would use bronze wire for the same reason for the bowstring. This bow was going to be hard to cock, so it would require a pump-lever design that would achieve full cock in four or five pumps on the lever. His current idea was to pump the bow to full cock, load the bolt by hand, aim, and fire. Slow, but foolproof.

Except for the bow part of the mechanism, this device was much like a Roman ballista. Jeff, Jr. even put a cup on the string so that they could hurl grenades, as well as bolts. It took about six weeks to get everything working properly on his ballista, but he was now ready to work on the bolt.

The bolt was about two feet long with rigid fins at the rear. The fins were set to impart a spin to the bolt to give it more stability than it would otherwise have. This would increase its speed over the same bolt using the drag stabilization that they were forced to use with the other bolts. The higher speed would increase the range, but, more importantly, would make it more difficult to dodge the bolt.

The warhead looked like a swollen bulge on the nose of the bolt. It was about three times the diameter of the bolt shaft. Projecting from the nose of the warhead was the firing pin. It worked by being pushed back into the fire starter by the impact of the firing pin against the target. Jeff, Jr. was considering going to a shaped charge, but this would take more design time than he wanted to expend at the moment.

The first tests of the completed system were very encouraging. He never had a failure of the ignition system, and some very satisfying explosions were produced by the new bolt. The shrapnel inside the warhead was made of rough lead balls about half an inch in diameter. They were dipped into scorpion venom before being loaded into the warhead. The warhead was loaded with 30 of the balls spaced as closely together as possible. These balls had wondrous penetrating characteristics—they cracked through exoskeletons like they were not there. It should take only one ball to effect a kill, so 30 balls might actually be too many; if so, the number could easily be reduced. The new warhead was so effective in knocking big chips out of the cliff face that he expected it to be effective against tanks, too.

Everybody was anxious to test the new weapon, but they didn't have any enemies close at hand to use it on. There were actually people standing around with little to do, so Jeff, Jr. proposed that they build a second armed car, similar to the first one, but having one machine gun and one ballista. They really felt that they needed to have such a vehicle on hand in case of another ant attack like happened to the expedition. Anyway, humans are highly skilled at rationalizing almost anything, so it was not hard to get people to work on the new armed car.

This armed car was built in record time and a crew was trained to handle it. One of the first jobs assigned to the car was to go out looking for a tank they could use for testing the capabilities of the ballista and the new ammunition. Jeff, Jr. insisted that he be the first gunner for the ballista so that he could get first hand information on how it performed.

They started out one morning to hunt for a tank. They were lucky and found one after only an hour or so of searching. Jeff, Jr. wanted to try his first shot into the beast's side, since that had proven invincible to all of their previous weapons. They approached a tank from its rear, and the vehicles were still so rare that the tank did not at first notice its presence.

The vehicle ran up parallel to the tank at about 20 yards range. The tank was idly walking, so the armed car slowed to about 5 MPH and Jeff, Jr. fired his first shot. There was no need for a second shot! The bolt hit the tank just behind its shoulder and reacted just as it did against the cliff face. The explosion knocked a hole in the beast's very tough hide about six inches in diameter. A number of the lead balls were driven into the animal's flesh, two penetrating over 12 inches. It was hard to say whether it was the shock of the explosion or the effect of the scorpion venom, but the tank took three more steps and collapsed to the ground. The animal was dead before the armed car could be turned around and stopped adjacent to the carcass.

This time, the humans were equipped with the tools necessary to remove the oh-so-tough hide and dissect the carcass. It was important to know how much and what kind of damage had been done to the tank by the warhead. A hell of a lot of work was involved in getting the hide removed and the animal cut up into pieces that could be taken back to Cavopolis. That's when they were able to collect and count the lead balls that had penetrated the flesh and see how far they had traveled. Overall, it was a very successful experiment. Both the meat and the skin proved to be a valuable addition to their stores. The skin turned out to be an excellent material for shoes.

Jeff, Jr. was convinced that they needed a contact fuse that would work with items like grenades that tumbled in the air before making contact with the target. The fuse in the explosive bolt would only work if the target was struck within a 15 degree cone. Otherwise, the firing pin would jam, and the warhead would not explode. He came up with several designs that would ignite the explosive, but they would not withstand the g forces of the original launch of the weapon. He just could not come up with something that was sufficiently reliable. Then, after more than a week of hard mental work, he had an inspiration.

He made a small compression-ignition chamber activated by the motion of a firing pin just as he was using on the explosive bolts. This he mounted inside a small hollow glass sphere. The unoccupied space inside the sphere was filled with combustible oil. By carefully tuning the system, he was able to get the fuse to float inside the sphere with a neutral buoyancy. Further adjustments resulted in a fuse that would always float so that the firing pin always pointed down under the pull of gravity. The idea was that the fuse would float inside the sphere and rotate as necessary so that the firing pin was pointing toward the ground. When the sphere broke under the shock of the weapon hitting the ground, the fuse would fall and set off the charge inside. That explosion would set off the larger explosive charge of the main weapon.

Oh, shit! This was so unreliable that it was not worth the effort. It was an elegant solution that was so complicated that too many factors had to line up. Jeff, Jr. fiddled and futzed with this complicated fuse for much too long before he finally admitted that he had to find something else. The something else he found had been staring him in the face the whole time, but he had not recognized it. What he settled on was a burning fuse! He had known that a piece of string soaked in a water solution of an oxidizing agent, such as potassium nitrate or potassium perchlorate, would burn at a steady rate, depending on the exact characteristics of the string and the amount of oxidizer soaked into the string.