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Approved Submission Ke-M2-W3900 Shoulder-Fired 20mm Railgun

Soban

Convention Veteran
Submission Type: Weapon
Submission URL: Ke-M2-W3900 Shoulder-Fired 20mm Railgun, 20x82mm Railgun Rounds

Faction: Yamatai
FM Approved Yet? No
Faction requires art? No

For Reviewers:
Contains Unapproved Sub-Articles? Yes, 20x82mm Railgun Rounds
Contains New art? No
Previously Submitted? No

Notes: The shoulder mounted weapons for the Mindy did not have a good anti-personnel option.
 
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FM approved for Yamatai.
 
If you want, you don't have to keep this weapon limited to anti-personnel. Because the 50mm is such a large round - as wide as some people's wrists - it's a pain to bring along reloads and additional ammo. If you bump up the operating velocity and expand on the rounds, it can easily work as a replacement or successor to the 50mm, which I think a lot of the troops would appreciate since it's less weight and volume to lug around.
 
I might try that, I'm not sure how you mean operating velocity, do you mean effective range? Also, what expansions should I make to the Ammo selection?
 
Sorry I wasn't more clear; I was referring to the projectile velocity. Since it's not as big and heavy as the 50mm, you can make it more powerful by just having it go faster. However, I advise against actually listing the muzzle velocity; just state in the weapon's history or about section that the rounds are smaller, and much faster than the old 50mm rounds. As for the ammunition article itself, I suggest simply changing the standard ball round to Tier 6, and the armor-piercing high-explosive to Tier 5.

The reason for this is that the APHE rounds sacrifice structural integrity to fit in that explosive payload, in return for popping something from the inside out should it penetrate.

Additionally, you could also include discarding sabot rounds for the weapon at Tier 7, with the diameter of the flechette being up to you. I prefer a 7.62mm/.30 cal one, though if you're feeling particularly humorous, you can go for a diameter of 9mm. Naturally, the tradeoff for its armor piercing ability is poor post-penetration effects.

EDIT: Is this a Gauss/Coil Gun or a Railgun by the way? It's one or the other, and I see the mention of coils as well as rails.
 
Alright, everything looks great, except for potentially one thing; the ammunition capacity.

The rounds measure 20x82mm, so try busting out your ruler or ruler app to take a look at what that'd be like. What I'm thinking right now is that even if it's in a more compact helical magazine, you'd only be able to fit maybe around 24 rounds in one that's around 8x35cm, accounting for the central shaft and other mechanisms. In order to fit one hundred, it's going to get really, really big, and that's the problem with its predecessor, the 50mm. It didn't take into proper account the size of everything, and in IRL, the basic 14 rounder could probably hold a gallon of water. My math is really rough, but if a helix mag around 8x35cm can hold maybe 24 or so, a 100 round helix mag will be massive

I believe that the SAoY prefers sleek, slim and efficient things in most instances, so having the basic mag be about that size and capacity would be idea. The backpack still has to fit on the back and avoid the wings on a Mindy, but there, I think 100 rounds would go well. You can go ahead and tweak the numbers to your liking, but this is the general ballpark I suggest landing in.
 
Here is the math,

Helical magazines are typically mounted either on top of or under the barrel. In bullpup designs, they could run the length of the whole weapon. So the length of a W2905 is roughly about 4 feet or roughly about 1.22 meters. The W3900 is shorter then that, say .9 meters because round numbers are easy. We round the length of the W3900 up to .09 meters. This means that in .9 meters we get 10 twists around the magazine. A double stacked helical magazine holds 12 bullets in a twist and is roughly 5x the width of the individual bullets meaning that the overall width is about 100mm or .1 meters wide. Therefore, 120 bullets is not in my mind out of the realm of possibility.

You might want to check my math as this is back of the envelope, but I think my numbers are good.
 
Your math is relatively solid, but here's something to consider; with a magazine that's both thick and long enough to house all those rounds, it's going to be not just big, but also heavy. They're practically solid tungsten or depleted uranium rounds after all, and that stuff has mass similar to lead. The gun armature will have to fight against that mass to bring its muzzle to bear, meaning it'll be less responsive. On top of that, it might risk making the pilot feel a little top-

Thinking about it some more, I suggest having three different magazine sizes to give players more flexibility. First, something with maybe 20-25 rounds, 100 and finally your pack filled with moar-dakka.
 

Hold the frell up. Why are you, a submission reviewer, attempting to alter this submission, @CadetNewb? @Soban and I originally meant for this to be primarily be an anti-personnel weapon, not an anti-mecha weapon - which is why the ammunition was originally rated for Tiers 2, 3, and 4.

Soban, I would strongly recommend that you restore the ammunition article to its original form, given that Cadet apparently "ignored" the part about the "...20x82mm rounds [being] designed to be extremely effective against personnel and retain a moderate degree of anti-armor capability."

With all due respect, CadetNewb, please refrain from using your authority as a NTSE reviewer to make changes that go against a submission's intended nature.
 
If I wasn't clear enough before, I'll say it again. In the end of the day, these are just suggestions and recommendations @Soban - if you prefer to keep the weapon as an anti-personnel one, then it can definitely stay in that role. It's just that there's already several very effective ones on hand, such as the wrist guns. They may be 'anti-armor', but they'll still kill a bug quite easily. If someone really wanted, they could even bring along an NSP, and it's hard to beat a good blaster.

EDIT: Thinking about it, another option would be to add frangible or fragmenting rounds, which break up on impact against tissue. This means there's a much, much larger transfer of kinetic energy, but also a much larger mess.
 
I did mean for this to be much more of an closer quarters anti-personnel weapon as @FrostJaeger mentioned. However, The qualities that make it effective in that role such as a shorter barrel, wider arc, and more ammo were not the ones that you suggested changing. The main thing that changed was it getting slid up the damage scale, which I'm ok with.
 
Advances in miniaturization allowed the barrel length to be shortened significantly.
Click to expand...
How long is it, then? The 2905 says its barrel is 4 feet. Especially given that this 20mm somehow has "better penetration and damage" than the 50mm, I think it's important to list exactly how much you've shortened it — and also because it's important for roleplayers to know the dimensions of their Mindy.
 
Reviewers are allowed to make suggestions, and may edit the WIP article with the submitter's permission.

If a WIP is edited without permission, you are free to revert it to a previous version.
 
Don't worry Wes, I wouldn't do something like that, and definitely didn't.

Anyways, after some talk on the Discord, it's my understanding that this was originally intended to serve as an analog to War Machine's gatling gun as a heavy anti-personnel weapon, and light-to-medium anti-armor one. Though I do like that idea, 20mm is not the ideal caliber for this job, since it takes up a hefty amount of space/volume. People have to lug the ammo around, and carrying reloads are a PITA since even ammo backpacks eventually run out, especially with high rates of fire.

The way I see it now, you can
  1. make the 20mm into a more refined successor to the 50mm shoulder canon for anti-armor work
  2. switch it back to the anti-infantry gun you originally envisioned
Also, don't forget to specify the rate of fire that the gun is capable of in full-auto. I personally prefer rounds per second since it's easier to swallow, however, I understand this will have to wait until you've selected which course of action to take. If you want to try and make a War Machine style gun though, I do suggest just making a rotary gun that's chambered in something that's 5-7mm. You just get more bang for your buck that way.
 
Perhaps you could have a "barrel kit" of sorts that changes the caliber. It's magnetically driven so a if the barrel and receiver are a modular kit it could make it compatible with multiple ammunition types.

That would offer fantastic flexibility since one mission may put soldiers up against many unarmored enemies while other engagements can take place between armored combatants and vehicles. Assuming the soldiers are aware of the expected forces they can prepare beforehand and bring the most appropriate equipment.
 
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