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Gunsmith Katsumi - Akitsukuni Arms Design Quest

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Character Sheet
  • Informational
    • Tachibana Katsumi

    Stress: 5/10

    Accomplishments
    Mechanical Engineering degree
    Got a job in your field
    Type 37 Special Purpose Rifle
    Type 38 Self-Loading Pistol

    Friends
    Maeda Rumi: Your roommate.
    Sanders Clara Rose: A colleague who works for Naylor, Sons & Daughters.

    Coworkers
    Mr. Watanabe: Your superior.
    Mr. Akutagawa: The boss of the company.

    Workshop 3
    Ms. Ikeda Nioh: Chemist. She also seems to be Mr Watanabe's personal secretary, but you're not sure if that's an official position.
    Mr. Yakade Yasuo: Physicist, specialized in ballistics. A living, breathing Technical Appendix C.
    Mx. Kusonoki Mayumi: Has a degree in materials science. Gets a look on their face when they say they know more about wood than anyone.
    Mr. Shiragiku Hideyoshi: Metalworker. Having met him, you've learned why metalworking is a craft and the meaning of the phrase "thinks himself heaven's gift to women".
    Mr. Kashiwa Ichiro: An apprentice gunsmith with a background in carpentry and actually using guns on people.

    Technologies
    Rifles (Familiar)
    Shotguns (Familiar)
    Pistols (Familiar)

    Rotate-and-pull bolts (Practical)
    Straight-pull bolts (Practical)
    Aperture sights (Practical)
    Stripper clips (Practical)
    Lever-delayed blowback operation (Practical)
    Double-stack magazines (Practical)
    Single-action handguns (Practical)
    En bloc clips (Conceptual)
    Simple blowback operation (Conceptual)
    Short recoil operation (Conceptual)
    Toggle-delayed blowback operation (Conceptual)
    Blow forward operation (Conceptual)
    Simple blowback operation (Conceptual)
    Double-action pistols (Conceptual)
    Automatic revolvers (Conceptual)
     
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  • Informational
    • Rifle is clearly leading with 25 votes against 12 votes for Machine Gun.

    I really think 'most accurate' fits a rifle far better than 'technically advanced'. Exceptional accuracy is an achievable goal working off of our previous work, and it's also where we can effectively make something new. Technical intricacy doesn't have a single clear direction to aim for, and it'll be much harder to make something noteworthy.
    Adhoc vote count started by Derpmind on Sep 28, 2020 at 11:24 PM, finished with 103 posts and 42 votes.
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    Derpmind said:
    I really think 'most accurate' fits a rifle far better than 'technically advanced'. Exceptional accuracy is an achievable goal working off of our previous work, and it's also where we can effectively make something new. Technical intricacy doesn't have a single clear direction to aim for, and it'll be much harder to make something noteworthy.
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    There have been a few reasonable suggestions (squad automatic weapon, carbine, bullpup layout, maybe SMG by an extremely generous reading), but I agree with you that an incredibly accurate rifle is easier, more visible, and more likely to be a hit :V
     
    I dunno about making it proper full automatic rifle. We haven't even made a semi, and to do it with any quality we're talking ww2 territory.
     
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    Vebyast said:
    The only solution there is basically to make the gun really heavy.
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    Not necessarily, there are two other ways: adding a shock absorber to the butt stock like in high quality shotguns or a recoil reduction system to the gun ala artillery guns or more relevantly the Triple Action Thunder

    E:
    Vebyast said:
    That said, gas operation would probably be incredibly difficult to invent on demand.
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    We already have plans on developing the ball lock into a ball delayed blowback system, or at least some of us are.
     
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    There's so many extra gambles we'd have to succeed at to make an automatic rifle that I don't think it's even possible. Take a look at this old option:
    Eukie said:
    [ ] A traditional Katzen-style bolt, copying the best features from the numerous Katzen-based sporting rifles you sell. (Skill 17)
    [ ] A straight-pull action, which you don't have a working copy of but you understand how they work. Sure to impress the Army. (Skill 14)
    [ ] Your brilliant and completely untested and unprecedented idea of a ridiculously smooth and fast straight-pull. Will blow the Army away, if you can make it work. (Skill 9, +1 Stress)
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    We didn't go with the "Revolutionary Tachibana-action", but if we had it'd have been a very difficult roll and it would have been stressful to do (with even more stress+delays if we'd had a bad roll.) But if we want to do this option in the new rifle, we'd be much more likely to succeed since Tachibana has gained the experience of making a high quality straight-pull. Building off of our precious successes, basically.

    If you want to create an automatic rifle, we'd have to succeed at creating multiple new technologies just to get it to even work.

    More generally, if we go with a Technical rifle, there's going to be a bit of a push-pull between creating new technologies and making components high-quality. So far both of our guns have succeeded because we've made every stat Average at worst, (minor flaws only,) and innovated just enough to put our design ahead. If we push too many new technologies, our quality is that much more likely to suffer. And our rifle has to be as high-quality as we can manage for our client.

    Meanwhile, if we go for an Accurate rifle, this option was available last time:
    Eukie said:
    [ ] Could be made to higher precision (70¥/rifle, +1 Accuracy)
    -[ ] Could be made to the highest precision (190¥/rifle, +2 Accuracy)
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    We can just buy our way to +2 Accuracy. We already have a solid base we can work towards our goal from. Even if we go for some risky choices and lose those rolls we'll still be on the right track to success. I can't say the same thing about a Technical rifle, not when there's no consensus on what kind of technically advanced goals people want to even aim for.
     
    [X] A rifle
    [X] Push the boat out, make...
    -[X] The most accurate gun you can engineer

    I might throw this in, just as well...
     
    Fakku said:
    7.92/7.62 CETME used a long aluminium/ lead-infused plastic core with a large copper shroud that acted as a flywheel. That round is probably the best example of easily understandable and reproducible kraut space magic I have ever seen. Would also help if we made a comp, threaded preferably.
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    To be honest I was thinking something like 7mm-08 Rem. Relatively low recoil, can fit in a smaller action for a nice portable package, and can take most game outside the largest bears in the country. 7.92 CETME is frankly beyond the materials science of Akitsukuni at this time, never mind the expense from using something so expensive as aluminum. Furthermore 7.92 CETME was made for a very different purpose, that is to say hitting a target at 800-1000m and be select fire. We are just looking for a very accurate hunting/target rifle. Granted this is a presentation piece to the Empress who is apparently an avid markswoman but her needs are very different.
     
    Sarpedon said:
    We are just looking for a very accurate hunting/target rifle.
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    There seems to be a bit of misunderstanding here. What I was advocating for was not the cartridge in its totality but taking the bullets design and using it in our 6.5 cartridge. Also, the actual constriction of 7.92 isn't that difficult even in our time period, it'll be expansive surely but possible. That being said 7.62 is even easier I mean look at it!


    FYI Plastica means plastic, which in this case was a type of Bakelite that we sort of have access to and Plomo means lead. IN our case we would be using the long one as it was designed specifically for use in MG at long ranges 800+m while still maintaining light recoil in comparison to 7.62 NATO(middle) and the assult rifle version (left) was so good you could acuretly hit a man sized taget at 500m in full auto, so yeah, want.

    Side note can anyone tell my why "insert image" is borked?
     
    'Sort of have access to' is not a phrase that fills me with confidence when it comes to conceptualizing something and then building a significant amount of objects that require a significant amount of precision.

    A worse ballistic coefficient makes things harder, for sure. You get punished worse for guessing the range wrong because the bullet decelerates faster and drops more by the time it reaches the target. This isn't too awful, but it's a minor inconvenience. If you have a known distance, it really doesn't matter one bit. It makes your wind guessing matter more, and you can't remove that unless you consider building a roof over the path between you and your target a valid solution, in which case, may I please have the use of your shooting range, your Imperial Majesty?

    If the round isn't precise, and manufacture of the bullet introduces a pretty nice spread of variables which can make the things less reliable in basically every way, none of it matters. Set it up on a braced rest in an airtight tunnel, shooting at a known distance, and you still won't outshoot the mechanical accuracy of the gun. You've got to be precise to be accurate, it's no fun having someone run out the world's biggest calibers to back your claim that the 30 yard group is centered closer to the middle of the target than any other.

    As a fun example of what can be done with a very precise rifle that shoots rounds with ballistic shaping and muzzle velocities better suited to softball than target shooting, Morgan James, a skilled rifle shooter and one of the guys involved with the first sighted rifle put up a group to show off the capabilities of his rifle at some point before 1860. One shot to sight in, and then ten shots at 40 rods (220 yards, which is conveniently close to 200 m)



    That picture of his group is full scale. The big circle is 1 and 27/50 inches in diameter.

    I don't want to know how much drop was involved in that shot, if you make me work out the numbers for how fast a ball slows down and drops I will probably enter some sort of depressive torpor.

    Accuracy requires precision, imo. We're not trying to meet the sort of requirements that only make sense for overly excitable futurists and people hearing a time traveler inexpertly describe infantry railguns.
     
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    Fakku said:
    7.92/7.62 CETME used a long aluminium/ lead-infused plastic core with a large copper shroud that acted as a flywheel. That round is probably the best example of easily understandable and reproducible kraut space magic I have ever seen. Would also help if we made a comp, threaded preferably.
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    Ah yes, the kraut space magic answer to "we want effective full-auto fire at a kilometer with an infantry rifle", possible the craziest design requirement in history.
     
    xthetenth said:
    'Sort of have access to' is not a phrase that fills me with confidence
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    I say that because we don't have any on hand, but considering it's 1912 I wouldn't be surprised if Mayumi can just drop by the local pharmacy and get the supplies for the stuff. Not sure what the rest of your post is about though. Unless it's unrelated to the first line? ILI5

    Mandolin said:
    Ah yes, the kraut space magic answer to "we want effective full-auto fire at a kilometer with an infantry rifle", possible the craziest design requirement in history.
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    Turns out the reason for that requirement was because Spain still had part of the Sahara and still actively engaged at 800+m ranges there.

    Also, check out this pick I found for a cross cut of the plastic rounds!



    E: I also found they tried to use ratshot on a 7.62 NATO as well as their own sabot trials but all the info I could find on them was that they existed.
     
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    Fakku said:
    I say that because we don't have any on hand, but considering it's 1912 I wouldn't be surprised if Mayumi can just drop by the local pharmacy and get the supplies for the stuff. Not sure what the rest of your post is about though. Unless it's unrelated to the first line? ILI5
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    Bakelite in 1912 is just getting into basic shapes and commercial production this is 1912 not 1952, it is very much not a mature technology and lacks the multidecade refininement that allowed the former Mauser men at CETME to make the thermoresin plastic that worked with the 7.92 CETME. Moreover with something like that you have any deviation in tooling or production quality, which will happen in 1912 when all this is done by eye, and it all falls apart. Stuff like that doesn't play well with a prestige project to be gifted to an Empress.
     
    Okay, so 7.92 CETME is an interesting concept. Problem is its construction requires a fair bit of precision or the round itself will be inaccurate. If the round itself is inaccurate, it doesn't matter one bit if it flies really well. The black powder gun I linked has considerably less margin for error when you're guessing wind and drop than any respectable smokeless powder gun, but it was finely made and shot by someone who knows how to use it, and he shot a group that I'd be happy to shoot a century and a half later.

    Basically in short, you absolutely must have precision in every part of the system if you want to make something that can set a new standard for accuracy. So I'm increadibly loathe to take on a ton of technical risk when we already have one world-beater in this very precise category, and in fact one that's frankly better (I know, I was surprised too).

    7.92 CETME is a product of a really weird thought process that's really been done twice, once for CETME to deliver the ballistics of 7.62x51 NATO at two thirds the muzzle energy, and once by the US with 5.56 FABRL, a fascinating thing that's basically 5.56 with less powder and a very long nosed cartridge that provides basically identical ballistics to 55 grain 5.56x45 M193 with 35% less muzzle energy. That's really what the idea of an incredibly long, light for caliber bullet with silly light construction and perimeter weighting to make the thing stabilize gets you, a lighter bullet with the same ballistics and less energy.

    There's just one thing, there's another way to get a lighter bullet with the same ballistics using less energy, and because of it 6.5 Akitsukuni is emphatically not 7.62x51 NATO. It, like 7.92x40 CETME, is also long for caliber, which means it's got similarly little drag force slowing it down (CETME does have the better form factor but not by nearly as much compared to rounds like 7.62x51 NATO), but CETME is very light, which means that force decelerates it more. The end result is that the only thing that sort of round does really well is being light and flying exceptionally well for its caliber, not overall.

    If we want to be super cool and make something lighter recoiling, just scale our existing round down to 6mm. Our 6.5 bullet blows CETME and its .2 G7 BC out of the water. It's heavy though, and to fly well with less energy we probably want to scale down a bit to keep muzzle velocity reasonably high.

    Mandolin said:
    Ah yes, the kraut space magic answer to "we want effective full-auto fire at a kilometer with an infantry rifle", possible the craziest design requirement in history.
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    Hot take, it was eminently doable with the technology of the time, they just went in the wrong direction by keeping the caliber fixed. They might not have realized the balance of things analytically, in fact I doubt it severely, but something like US 6x45mm SAW uses yet less energy to get similar drop performance, and considerably better wind drift. That said, 66% energy for very similar ballistics to 7.62x51 NATO is not bad in the slightest. It's just that there's better yet to be had, and we've already got it.


    Okay, now I'm frustrated that people apparently forgot about 6mm SAW, that's a good round.
     
    After checking some more stuff on the plastic rounds, yeah not really worth the effort. I was so blinded by the majesty of KSM that I forgot it's vital flaw, that being KSM is a solution so complicated it loops back to seeming to be a simple one.
    xthetenth said:
    Okay, now I'm frustrated that people apparently forgot about 6mm SAW, that's a good round.
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    Apparently Hornady didn't cuz they released what is basically an updated version called the 6mm ARC 4 months ago, and its already been adopted by some branch in the military, possibly SF considering that the gun they requested is a DMR.
    Mandolin said:
    Hey, what if we made a scope that doubled as an auto-zeroing coincidence rangefinder? Rangefinder cameras were a thing in the OTL 1910s
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    Certainly possible but not recommended, in order to make a rangefinder that can accurately measure 1km+ ranges you'll need it to be at minimum a foot long. That being said, making one for a possible future sniper teams would certainly be nice. Plus if anything we can just copy the POS-1 reticle with its installed rangefinder table. Or mill-dot if you wanna do a lot of head math.
    Parzival95 said:
    Illuminated optics?
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    Maybe? Depends on whether or not @open_sketch says LEDs where developed in Gaya as opposed to just ignored after their discovery in 1907. Barring that we can try to make one using tritium lamp as a light source.

    Side note did you now that the Reflex sight was invented in 1901, but didn't go big in small arms purely because the lights they used were so big and power hungry? The original actually used natural sunlight and was reported to be vary good for quick sighting targets at up to 300m or so but was rendered useless whenever a cloud blocked the Sun.

     
    Fakku said:
    Maybe? Depends on whether or not @open_sketch says LEDs where developed in Gaya as opposed to just ignored after their discovery in 1907. Barring that we can try to make one using tritium lamp as a light source.

    Side note did you now that the Reflex sight was invented in 1901, but didn't go big in small arms purely because the lights they used were so big and power hungry? The original actually used natural sunlight and was reported to be vary good for quick sighting targets at up to 300m or so but was rendered useless whenever a cloud blocked the Sun.
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    Neat!

    Tritium isn't bright enough to make a reflex sight work, I'm assuming? I bet you could make one that works at night, but it wouldn't be bright enough for daylight. Maybe different modes, like, a cap with tritium on the inside that lets in sunlight when there's enough of that or flips down to provide an illuminated sight at night?

    Apparently there's also a variation that works with much dimmer lights at the cost of adding a third axis to keep track of and you have to keep both eyes open.
     
    Fakku said:
    Apparently Hornady didn't cuz they released what is basically an updated version called the 6mm ARC 4 months ago, and its already been adopted by some branch in the military, possibly SF considering that the gun they requested is a DMR.
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    Yeah, that's on my short list with .224 Valkyrie, and it's impressive for sure, though I'm not sure if it'll win that particular head to head. It isn't really the same though, it's limited in its dimensions by the requirement to fit in an AR-15 magwell, though 6x45 SAW looks like it was kept somewhat sedate. All of those rounds that are built into the AR-15's magwell and bolt face have some limitations though. You've got 57.4 mm to play with, and increasing the base diameter of the cartridge means cutting material out of the bolt face. 6.5 Grendel bolt faces, like the 6mm ARC uses are pretty darn thin. The 6.8 SPC bolts that .224 valkyrie uses have a bit more material and a bit more strength, and that's reflected in the maximum pressure rating that each can handle. Apparently you can get a good bit more performance out of all of them with a bolt action and loads that are past the SAAMI spec but well within reason on a stronger action.

    Modern propellants (and if I'm being cynical the manufacturers using long barrels for their muzzle velocity claims) have picked up a lot of slack, but I feel like there's still a happy medium for 6mm between 6 ARC which is a bit constrained in length and pressure to the point where 223 caliber might make more sense and 6 creedmoor which is quite a lot and somewhat notorious for barrel wear. It's not a nearly drop-in solution like all the rounds that are just a different bolt face, chamber and magazine for your AR, so it probably won't get explored.
     
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    3-2 Akitsukuni Nadeshiko
  • Threadmarks
    • "The name of the game is accuracy. We're going to build a rifle that beats the world, shows the strength of Akitsukuni arms, and honours the Empress."

    "You're going to need the original load for the six five, then," Yadake says, a satisfied smile spreading across his face.

    You nod. "I want to review our options before deciding on any of the details, but I really do want to use that round for something."

    "Tunnel boring? Warning ships in fog?" suggests Kusunoki.

    You sigh, some part of you wishing Kusunoki would return to just making crude comments.

    Shiragiku composes himself: "I don't know if we need to go as far as the super six five, the standard one is a really good marksman's round and I can run off a few hundred match-grade versions for the presentation easily. Then all the dignitaries watch Her Majesty hit a boar a kilometre away and order themselves a Type 14 from us."

    "Less work for us too, if we don't have to do a new round." says Kashiwa.

    You think about this for a moment, but Kusunoki interrupts you:

    "Wait a minute… does the Empress even like hunting boar?"

    "Uh, well," you begin, "we should have records of ammunition purchased by the Palace, so…"

    "That doesn't tell us what the ammunition is used for," Yadake notes.

    "Or who uses it." puts in Shiragiku. "But it's better than nothing."

    You nod. An idea of how to proceed forms in your head and you start assigning tasks. Yadake has pretty much set himself the task of looking at bullets and you're happy to let him do that for now. You task the rest with finding ways to limit mechanical inaccuracies in the rifle itself, then go to find Ikeda. She has her own ideas of how to proceed, and that keeps you occupied for the rest of your half-day.

    ---

    Your arrow smacks into the backstop in the seven o'clock position in the outer ring and quivers slightly. You watch it suspiciously, you've had too many fall back out of the target, but it stays where it is.

    "I've had a thought." says Rumi, turning to face you. "About Her Majesty's gun, that is."

    Your next shot goes to three o'clock.

    "What sort of shooting does She do? You'll need that before you make a gun."

    You pause for a moment: "Ikeda got me a whole load of old newspapers and gossip rags, but it was very difficult to get anything useful. It's all oblique references and talking about what people near the family are doing. As best I can tell, She likes shooting and generally does targets rather than hunting. Or at least, we ship more ammunition to the Imperial Palace than we do to her estates."

    Your final shot of the three lands at ten o'clock in the outer ring again. Your accuracy is fine, on average you've hit the bull. You need to work a little on your precision, though.

    Rumi steps up and slots the first of her three arrows home in a moment.

    "I don't know about target rifle shooting…"

    The second arrow follows the first.

    "...but when I'm doing archery I do short range…"

    The third arrow slips between the first two, into a tiny gap, and when it hits the target it knocks the second one back out.

    "...high accuracy, high speed stuff. That's what's most fun, getting the whole thing to flow."

    You think about this as you step up to collect the arrows. You hadn't really considered a rifle that emphasises handling and short range shooting, when you had said 'accurate' you were imagining something to fell deer across the breadth of a valley. As you wander back, Rumi seems to be struggling with the next part of her thought, so you stop for a moment and look at her.

    "She… The Empress… The Empress is a traditional Akitsukuni beauty…" She looks around a little and then whispers "She's quite short, Katsumi."

    Well, how dare she! That's practically treason, and besides, The Empress is taller than you. Nearly five feet tall!

    Rumi reads your face: "Yes, I know, I know, but you've got to think of these things. I remember when you were talking about your new rifle you said that recoil was like draw weight, right? Well, I wouldn't give Her Majesty a big men's warbow."

    You silently drill your next three shots much deeper into the target than usual, and much less accurately, but by the time you're packing up to go home you're wondering if Rumi might not have a point.

    ---

    The trolley rattles to a halt next to the park and the low morning sun lancing into your eyes wakes you from your design-daydream for long enough that you remember to get off. When you unlock Workshop 3 you take advantage of the quiet to think about what an underloaded 6.5 cartridge would look like. You retrieve one of your books on internal ballistics that has somehow migrated to Yadake's desk and flip through it until you find the equations you're looking for. If you reduce the powder load by this much and the length of the casing by that much...

    You'd get a gentler cartridge, but is it worth sacrificing long-range performance for? You wander over to the tea pot and poke life into the fire. As the water comes to a boil and you pour it over the tea leaves, you feel you have to make a decision:

    [ ] Yadake's High-Velocity Super 6.5mm​
    [ ] Imperial Matchlock's Standard 6.5mm Akitsukuni​
    -[ ] Apologise to Yadake and promise you'll find somewhere to use Super 6.5 (+1 Stress)​
    -[ ] You really don't need to encourage him​
    [ ] Your Short 6.5mm​
    -[ ] Apologise to Yadake and promise you'll find somewhere to use Super 6.5 (+1 Stress)​
    -[ ] You really don't need to encourage him​
    [ ] Something completely different that you've been thinking about since the Rifle competition (Write in)​
     
  • Threadmarks
    • [X] Yadake's High-Velocity Super 6.5mm

    Surely we'll have social acceptance for making a padded stock for this rifle. Anyone who buys subsequent models will be too insecure in their physical prowess to complain about the recoil. :V
     
    Eukie said:
    "She… The Empress… The Empress is a traditional Akitsukuni beauty…" She looks around a little and then whispers "She's quite short, Katsumi."
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    Whelp. I regret everything. Can we go back and make a pistol instead?

    [X] Yadake's High-Velocity Super 6.5mm

    If Anime's taught me anything, it's that short girls get the biggest guns. Refuge in audacity Anime, SV!
     
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