RCFC R&D

[Rusty]

Now that the design phase was complete, Rusty had to actually make the thing.

To that end, he converted the CAD file into something the 3D printer could understand, and loaded it with the appropriate materials.

The casings would be made in two halves that would be glued together using an impressively strong epoxy. That was all well and good, but before the gluing would come assembly.

The combustion chamber for the rockets specified a strong, lightweight durasteel allow that could handle the incredible pressure of the solid rockets he'd use to propel the projectile. A billet of the alloy, along with the plans, were fed into the CNC milling machine.

While both of these went to work, Rusty started putting together the shaped charges. The writer will not go into detail on exactly how this is done, for reasons that should be obvious.

 

[Rusty]

In a few hour's time, Rusty had all the components laid out and ready to be assembled.

There wasn't much in the way of electronics for the projectile. No fancy chips, no rangefinders or electric detonators. It was all simple chemistry. Mechanical detonators had their own set of issues, namely reliability. There was about a 1 in 30 chance of a dud, and there simply wasn't enough space for redundant blasting caps. But EMPs weren't going to be an issue, and there wasn't a chance a stray radio signal could interfere with the chip and cause premature detonation.

No one liked premature detonation.

A few pellets of a high energy density propellant went into the combustion chamber, which was capped off by a heat resistant nozzle. Into the mouth of the nozzle went the fuse, which would be sparked by the powder charge and would burn for a fraction of a second before touching off the rocket motor.

The shaped charge went in next, along with the blasting cap that would detonate it as the nose cone was crushed against the target. Once all that was together, Rusty carefully glued the two halves of the round together. It would take some careful sanding to make the seam perfectly smooth, but it was a small price to pay for perfection. Or at least it would be if there wasn't a chance that the static buildup could set off the explosives. Thankfully that wouldn't be a problem once the rounds were together. The copper cap that held the primer on the shell would ground off against the weapon or the magazine.

 

[Rusty]

All told, Rusty had 15 rounds with which to test. Gooooood, gooooooood.

Now he just had to prep them so they could be loaded in the shells.

First off, using a very fine grit sandpaper and some grounding clamps, the Shard smoothed out the seams and any rough spots left over from manufacturing. This was delicate, dangerous work. Even with the grounding clamps, a spark could cause a premature detonation, and that would be bad. Fortunately, it went seamlessly.

Minus 5 points for bad puns.

Next came the paint. Rusty put the rounds in the paint booth and programmed it to spray them down with a coat of static-resistant primer that would further reduce the chance of a spark, followed by a coat of bright yellow that would allow the high speed cameras to track them in flight. The production batches would probably be matte black or olive drab, but those colors tended to show up poorly, and it was important that the Shard get an idea for the flight characteristics.

Once they came out of the paint booth, he gave them one final inspection. One round had to be discarded. The bright yellow paint illuminated a hairline fracture in the casing that would have likely caused catastrophic failure when fired. That was not a good thing, but he thought he knew what had happened. This shell had been the first in the batch, and the printer occasionally had a hiccup when printing a design for the first time. They probably wouldn't have that issue again, but each round was still checked for a second time, just to be sure.

 

[Rusty]

Loading the rounds into the shells was the easiest part.

The powder charge went in first. It wasn't a lot as far as these things went, but it was definitely enough to get the job done.

Over the powder went a wafer of combustible flimsi. It wouldn't act as a wadding, exactly. Its purpose was mainly to keep the powder from getting up around the rocket's spring loaded fins, where it could potentially gum them up. The fins were vitally important. Since the round wasn't spin stabilized, they were all that was going to keep it on target. The flimsi would be completely consumed by the explosion that ignited beneath it, so that it wouldn't interfere with the rocket's ignition.

The next step was to carefully lower the rocket into the shell, snugging it down as far as it would go. Rusty could produce a fair amount of force just with his fingers, but the pressure wouldn't be steady enough to completely seat it without risking something getting knocked out of alignment, so for the next step, he took the round over to the loading press. Steady pressure was the key here. A sharp impact could potentially set it off, and that was no good.

The press worked as advertised, however. No premature detonations here.

When it was finished, the shotgun shell looked like any other. The only way to tell the difference was to pick one up, as the round was noticeably heavier. For the finished product, the Shard would make sure each shell had an identifying marking of some kind to more easily distinguish it from its mundane brethren.

 

[Rusty]

For now, Rusty only finished one round. He didn't know if this powder load was going to be too much. The round was about three times the mass of an ordinary shotgun slug, but it would be travelling significantly slower too.

Only one way to find out. The Shard loaded it into the a single shot 12 gauge, one specifically designed for testing. It was fitted with a series of sensors that would provide data on everything from pressure in the bore to muzzle velocity to recoil. It was securely mounted to a stand and could be fired remotely. There were some rounds he didn't mind test firing the first time by hand, but that wasn't the case where explosives were concerned.

Once the weapon was hot, Rusty retreated back behind a blast shield. He was sure his math was good and that it wouldn't blow up, but one misplaced decimal point could have dire consequences. Get the charge a little wrong, or seat the round just a little crooked in the shell, or break a fin, or any one of a hundred different little things, and at the very least, he was building a new test gun.

Like it or not, safe meant behind something solid, at least at first.

Everything was set. The Shard double checked that the range was clear, then pushed the fire button.

The first thing he noticed was the noise. The report from the shotgun was loud, but the racket the rocket itself put out was simply incredible. The round tracked straight and true, all the way to the durasteel target 50 meters down the line. It was hard to tell for sure without looking, but the remote cameras made it look like there was a neat hole punched clean through, about a centimeter in diameter. That part looked to be a success.

Unfortunately, the data that came back from the test gun was less positive. The round had achieved the desired muzzle velocity, but the recoil was enormous. No shooter worth the name would want to deal with that. The next rounds would have to have their powder charge halved.

 

[Rusty]

Once the powder charge was reduced, things went swimmingly.

A muzzle velocity of 200 m/s was not a lot, all things considered, but it was still more than enough to be lethal right out of the barrel, and the rocket booster quickly sped things up to far more a far more respectable velocity. For safety's sake, Rusty wouldn't recommend shooting at anything closer than 10 meters, but that was for the shooter to decide.

The maximum effective range was about 50 meters. The rocket could easily travel much further, but shotguns were not equipped for long range accuracy. Most simply didn't have the sights for it, and even shotgun optics were dialed in for snap shots at close range rather than sniping. And past 50 meters, the noise and the smoke trail would easily give your average Force user time to react and get the [bleep] out of the way.

The armor piercing capabilities were about what Rusty had figured. The rounds had no problem punching through thin armor of the sort one might reasonably expect to wear in combat. They handled sheet durasteel with aplomb, and even managed to crack the vonduun crab armor simulant that the Shard had bought at great expense. However, the charge simply wasn't enough to punch through thicker armor, and would be useless against exotics like phrik or beskar.

The rounds also worked well in the different test weapons. The pump action was fine. The robust operating system had a long history of performing well even with unusual ammunition. The gas operating system also performed well, though the Shard did note that the gas pressure was on the low end of its tolerances. If the weapon got excessively dirty, the chances of a jam would go up dramatically.

Still, it was an overall success, and Rusty was pretty sure he had a marketable product.

 

[Rusty]

This next project was ridiculous.

Rusty knew it was ridiculous. Even if he could make it work, there was no way in hell it would be practical.

The design called for a quad-barreled carbine with heavy bullets that could punch through armor. And it had to have the galaxy's most impractical blade to boot. But hey, a job was a job, and this one should be fun.

The first step was picking out the round. The project called for antiarmor capabilities, which was going to be tricky in something ostensibly the size of a carbine. That meant big effing bullets. The fact that the thing was going to weigh a ton would cut down on the recoil, but that didn't make it any more practical.

[Bleep] it. Time to break out the Beowulf.

The .50 Beowulf was a specialty round designed to combine the excellent stopping power of half inch handgun bullets with a design that could more easily be fed through automatic weapons. They were originally intended to be the go-to round for military checkpoints, as their utility in stopping lightly armored airspeeders and the like was unparalleled. Unfortunately, since the round couldn't be used in existing weapons without extensive modifications, the military procurement officers had deemed it an unnecessary waste. They reasoned it was worth putting a few extra bullets into something to stop it, if it meant saving several million credits fielding a new weapon system.

Despite the initial setback, the round had quickly gained popularity among private shooters, who valued the extra stopping power when hunting large game. They didn't mind dropping a few grand on a new rifle, and had kept the round alive long after the military had dismissed it.

Rusty had always had a soft spot for it in his crystalline heart, and was more than happy to put it to use.

Unfortunately, deciding to use it was a whole lot easier said than done, as the weapon he was going to have to build would surely be one of his most complex creations to date.

 

[Rusty]

Right. Now onto the hard part.

Four barrels meant four chambers, which basically called for four complete guns in one. That was going to be a [bleep] and a half.

There were some ways in which he could make life easier on him. The rounds were designed to work in anything that could extract 7.62, which meant he didn't have to custom build everything. He could use 4 AR-10 upper receivers and just mill out custom barrels. He'd still have to figure out how to mount them on a common platform, and he'd also have to integrate the gas tubes so one trigger pull would fire all four uppers in sequence. That was going to suck.

Alright, barrels first.

A project like this would call for heavy barrels. The Beowulf rounds were fairly high pressure, and the volume of fire this thing would have to handle also presented durability challenges. That was fine, but it would take an hour to mill out a single barrel, and the CNC machine could only handle one at a time. That would give the Shard to sort out the cluster[bleep] of a gas system.

 

[Rusty]

[Bleep].

[Bleep]ing [bleep] son of a [bleep] licking [bleep].

These gas tubes were going to be the death of him.

Rusty had tried some really crazy stuff, but linking the gas tubes from four AR uppers together in a way that made sense was something new. This was the definition of insanity. There would have to be a specific firing order if this was going to work right.

The base gun, the one that would kick the whole thing off, would be designated Alpha. To the right, canted at 90 degrees, was Bravo, the second weapon in the firing order. Go another 90 degrees, this one upside down over Alpha, was Charlie. The final gun, in between Alpha and Charlie, was Delta.

Alpha was the only one pinned to a lower receiver. Its gas tube would be hooked to Bravo. When it fired, its gas would cycle the bolt for Bravo. Bravo would cycle Charlie, Charlie would cycle Delta, and Delta would cycle Alpha. It was important to note that each upper would still have to be triggered independently, but what could you do?

The gas tubes were relatively thin, lightweight aluminum. It could be bent to an extent, but it couldn't be stretched or crimped. Anything that impeded the gas flow could lead to a catastrophic blowout, and likewise if it was weakened too much. That meant he couldn't use the originals, as they just weren't long enough. He had to know roughly how they had to run before he could fabricate the bracket that would tie it all together, but he couldn't hook anything up until the bracket was done. And he couldn't start on the bracket until the barrels were done.

This was going to be a gigantic pain in the [bleep.]

 

[Rusty]

Finally, the barrels were done.

Well, they were milled, at any rate. They'd still have to be bored, rifled, finished, and then blued, but that would all come later. For now, Rusty had to get the T-shaped bracket that would hold the uppers together built.

Here, he was perfectly willing to cheat a little. Each upper receiver had an integrated rail system build in. The Shard planned to make use of that by designing the bracket with that in mind. It would clamp down on the rails, which would hold the weapons securely in place. It would hold them all together, but if he did it right, would also allow the point of aim to be adjusted somewhat. Dialing all that in would come later, however. For now, the bracket.

There would be five basic pieces: the brackets clamps that would connect to the uppers, as well as the central piece that would allow them to be adjusted. Ideally, the weapon would be zeroed to thirty meters, with preset adjustments to allow it to hit as close as 10 and as far as 70. Not great as far as such things went, but too much movement would put undue stress on the gas tubes, and that was dangerous. The end of the bracket would be capped with a laser rangefinder that would automatically compensate for the range of the target and get the point of impact for the massive slugs as close together as possible.

Milling and assembly took a little over three hours. Once it was all put together, he got the rifles clamped down and, once he was sure the adjustments were correct, locked them down tight and sealed the mechanism with a durable epoxy that wouldn't allow them to work loose.

Next up was hooking up the gas tubes.

 

[Rusty]

Did you know that gas tubes are among the most annoying, fiddly inventions ever to come out of the human mind?

Rusty did. He hated them with a passion. Given his choice, he'd much rather work with gas pistons than direct gas impingement. Pistons ran cleaner, cooler, and were much less likely to foul the weapon and make it jam, or worse, clog and explode.

Unfortunately, pistons simply wouldn't work for this system.

And so there was a lot of swearing, bending, flaring, soldering, and then starting it all over because this tube or that was a millimeter too short. Everything had to line up perfectly, and there was no margin of error.

The Shard suspected that jobs like this got easier with time, but he had never been one to fiddle with overly complex gas systems like this. He preferred weapons that were, either simple and rugged or overpowered enough to justify the effort. This was neither. It was, however, a paycheck, and that's what mattered.

So he dealt with the annoyance and vowed never to take a job like this again.

 

[Rusty]

Once the tubes were in place, it was time to rig up the firing system.

If Rusty was in the mood to get fancy, he'd install a gas block in the firing tubes to manually trigger the firing pin on each weapon. Unfortunately for the poor bastard that would have to use the thing, he wasn't in the mood. Far easier to install a small servo in bolt assemblies B-D that would fire in sequence. When the trigger on A was pulled, it would send out a minuscule radio burst that would trigger the servos.

Each servo was on a timed delay. The process would start at the same time, but the delay would increase in increments, so as to allow for a precise burst. Functionally, the weapon would fire like a normal AR-series rifle on burst fire. That meant less for the shooter to worry about. Effectively though, it was a tightly choreographed dance, and if one part failed, it could potentially mess up all the others.

The devices themselves were about the size of the cap on a ballpoint pin. They operated on the same principle as a coil gun: a current would travel through the coils, generating an electromagnetic field that would push an object in a given direction. The object in this case was a striker that would impact the rear of the firing pin with enough force to cause the pin to detonate the primer. Once the field was gone, a spring would reset the striker to its original position.

Building three of these things from scratch was a pain. Rusty didn't have coils small enough, so he had to wrap them by hand. He also had to find components small enough to work in the confines of the servos. For power, he went with a piezoelectric battery that would be recharged by the motion of the bolt being rammed rearwards by the gas impingement system. The radio receivers were similarly tiny, and had to be hand built and calibrated, as did the tiny logic circuit that would time the whole thing.

If he didn't have the inherent patience of a rock, the Shard wouldn't even bother trying. As it was, he consigned himself to long hours at the work bench with a soldering iron.

Finally though, he had everything dial in and secured the servos in place in their respective bolt assemblies.

 

[Rusty]

Now came the time to design the shell that would cover the whole thing up.

Rusty wasn't in a mood to get fancy at this point. He opted for a large box that would envelope all four rifles and associated hardware. Each rifle would have a designated magazine well and ejection port, but that was about the extent of the access he could allow to them under duress. Modern cartridges burned fairly cleanly, which would reduce the chances of fouling, but too many openings allowed too many opportunities for dirt and other environmental factors to enter, and that wouldn't do at all.

The customer would still have to be able to access the internals, which meant the shell had to be removable. To that end, Rusty designed it to split open like a clamshell. On one side was a set of concealed hinges. On the other side, the two ends would meet flush, and would be held together by some bolts. It would take some time to work it open, definitely not a task to be accomplished under duress, but slow access was better than none at all.

The shell would of course have an integrated rail system, in order to accommodate optics. There were a few on the market that would allow the customer to accurately aim his very expensive and wildly impractical toy.

Once he had the design drafted up, the Shard plugged it into the 3D printer and watched it go to work. The shell would be made out of an ultralight, ultrastrong composite material that would greatly reduce the weight, though he still suspected the final figure would exceed 10 kilograms.

 

[Rusty]

By now, the machinery of the somewhat inaccurately named paint booth had finished with the barrels. They were fully rifled, blued, and free of any burs or defects that might hinder performance.

Actually affixing them to the upper receivers was easy enough, though he once again had to fight with the gas tubes to ensure that they all lined up properly.

If ever he could get his hands around the neck that fed oxygen to the brain that designed these infernal things, he would do so with glee.

The muzzles were all threaded to allow for muzzle brakes, which would be essential for accurate rapid fire. The idea behind the muzzle brake was to channel the gas from the round in useful directions. A firearm's point of aim tended to climb under rapid fire, so the brakes would divert gas upwards. Gas moving upwards tended to push the barrels back down again. It wasn't perfect, but it did reduce the climb enough to make it worth the effort.

Once the barrels were installed, the brakes fitted, and the clamshell case complete, Rusty put everything together for final assembly.

The gun was all kinds of ugly. There was no helping that. Form had to follow function in his business, especially with military grade hardware. Civilian shooters could afford to tart their guns up however they wanted; it was unlikely they'd need them as anything more than conversation pieces. Utility weapons, even vanity pieces such as this monstrosity, were utilitarian to a fault. They had to be. Too much fancy artwork could catch an enemy's eye. That was, generally speaking, a very quick way to get shot.

 

[Rusty]

And now it was time for final assembly.

Most everything was good to go. There were some final adjustments to make, and a little bit of finishing work. There was no need for an external selector switch, as the weapon was only capable of firing on burst. The laser rangefinder would automatically zero the weapon to the desired range, which meant there was no need for a manual adjustment for that.

Honestly, this whole thing was way too [bleep] complicated. There just wasn't any other way to do it and still get the requisite 10 posts for a development thread.

Once everything was put together, Rusty broke it all back down to make sure it could be done, then reassembled it. It was almost time for the final test fire, and then it would be finished.

 

[Rusty]

The test fire went smoothly enough.

It took some time to calibrate the point of aim properly. It wasn't like sighting in a normal rifle. With this one, you had to make four bullets converge more or less on the same spot, or or was useless. Each weapon had to be dialed in individually, and that was a pain in the [bleep]. Still, it could be worse. The bracket was articulated in such a way that individual adjustments were possible, even if they were a little bit of a pain.

Eventually everything was dialed in. Rusty loaded 4 magazines, each with 20 rounds apiece, lined up on the target, and unloaded the big unwieldy [bleep].

The racket was incredible.

It might not hold a candle to Gertrude, but there were few things that did. Gertrude was a force of nature in a league of her own. This thing, it was a beast of a different color. The big Shard found himself leaning into the weapon, and it still managed to force him back. By the time all 80 rounds were expended, he had to take no less than three steps back, just to keep from getting knocked on his rear.

Whatever poor human ended up with this thing was in for a treat.

The rangefinder worked well enough, though there was a noticeable lag in between acquiring the target and the adjustments. That wouldn't be too big a problem, but it was yet another in the long list of things that made this weapon useless.