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Sturgeon's House

Sten

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Posts posted by Sten

  1. Yes, I have read the paper, but it has been a while so I probably forgotten stuff, so a re-reading is in order. That goes for the interview as well. I knew Textron was using a compacted powder bed, but it sounded so weird I wanted confirmation. Doing probably simplifies the molding process and does not lock you into a specific bullet shape. I think I'm starting to understand the reasoning behind it.

     

    As for the action displayed, I'm also aware of them. To be frank I haven't paid much attention on the LSAT or MGs in general, more interest on the rifle and rifles in general. That VPN's animation sure is handy in explaining the concept, but he based it off the first part of the patent, the one that just displays the idea of a rising chamber and rammer, without the so called headspacing solutions. As it's I guess you can get away with just sizing the chamber and case just right, specially if one remembers cases also expand axially not just radially. But actually forcing the case to mate against the barrel would make a better consistent seal and would lax the fitment of the actual chamber. After all they went to the trouble to patent it... but maybe they can get away without using nay of those, other designs did like the Steyr ACR.

     

    Other people, with extensive knowledge of firearms and engineering and which are keeping track of the program, which I have spoken questioned the accuracy of the animation "That animation is hilariously incorrect"... and considering how misleading and vague patents can be I will keep it as a possibility, but neither will take his word as gospel because no further confirmation was provided.

     

    In anyways, thanks for the info and for clarifying the point about the seating. I will be sure to re-read the paper and the interview.

  2. On 9/14/2020 at 7:32 PM, SH_MM said:

    C.G Haenel has beaten Heckler & Koch for the German G36 replacement program. The weapon performed a bit better and was more "economical".

     

    https://augengeradeaus.net/2020/09/neues-sturmgewehr-der-bundeswehr-soll-von-haenel-kommen/

    I don't think anybody was expecting that result, myself included. From what I could gather from the news and from talking people in the gun industry and German speakers it appears to be solely a case of "it meets the requirements... and is cheaper"... which itself raises questions about the result, considering the size and ownership of Haenel, some even going as far as calling it a shell company for Caracal. How much of that is true or just "foreigner man bad" I don't know.

     

    As for the rifle it's quite sad to see a new design fail, even if it also met the requirements. For the Haenel I've heard that it's heritage goes both ways "designed by the same team that did the hk416 and Sig" or "A clone of a clone".

     

    Let's see what legal sheenanigans will happen next.

     

     

  3. So, for a while I've fascinated about Cased Telescoped Ammunition (CT ammo for those weird people that like acronyms), after, of course, laughing at the idea like any uninitiated simpleton (dum fix wat aint broke!) until I actually understood the idea and a presentable firearm came along and caught my interest, the current iteration of the Textron carbine/rifle/whatever in the NGSW program... because until this point all small arms examples were either goofy as fuck (Dardick), stillborn (Ares AIWS), or weirdly specific (Steyr ACR being and open "bolt" flechette gun.)

     

    Then I researched and talked to knowledge people and comprehended the advantages of the concept, along with plastic cartridge cases: The near total elimination of small parts and movements from a gun's action, now using simple large parts and gross movements, the controlled nature of the feeding and ejection cycle, the cartridge case being fully supported in the chamber which allows for simpler design and analysis along with higher pressures, a more compact design (albeit highly dependent on the external constraints and capacity and projectile proportions), a potentially much simpler and stronger breech and locking mechanism, sealed ammunition, cannelure free sleek bullets, no more worries about hardened penetrators tips eroding the finish of the gun's inside, the ability for the gun to be able to function even with a severe misalignment of the chamber and barrel, etc... In short I was sold on the concept.

     

    Yet... I never quite understood a few, small and not very often talked details about this type of ammunition configuration. So I kept researching, learned a few things, saw the historical development, older takes on the idea, which also raised more questions:

     

    The first being, how is the projectile seated in the current version of Textron's Cased Telescoped ammunition? As you can see the only solid point of contact the bullet has is of the ogive on the cap, which stops it from going forwards under handling and provides both a seal of the powder chamber and pressure for the shot start... but nothing apparently stops the bullet from going further inside the case.

     

    US09267772-20160223-D00000.png

    DA09IVYXUAAd7ce?format=jpg&name=large

     

    From what I could gather talking with another engineer and gunsmith that did research on the subject, the bullet apparently is seated on a bed of compressed spherical powder... that.. can work... I guess... but it sounds extremely questionable, specially in regards with consistency, but perhaps it work. But that is not the only reason I'm questioning this detail:

     

    US4770098-drawings-page-2.png

     

    As you can see on this patent by Eugene Stoner the cartridge has the same sort of contact of the cap and ogive, but the bullet base also rests on three ribs/webs (technical terms are the hardest part of translation.) Those "things" also apparently serve to improve flow of the plastic during injection molding and to strengthen the case at a minimal internal capacity penalty

     

    This way of doing things seems like the natural and proper way of seating a bullet, solidly and repeatably... so the Textron version looked so weird I imagined they were gluing the bullet like True Velocity possible does on their ammo, they aren't also using the canellure or other type of groove to secure the bullet (not that it would be a good idea)... so why did Textron opted for what they are using? Reality often is unintuitive as fuck  so there must be a reason for that.

     

    Other big question I always had was how exactly the obvious issue of gas leakeage, analogous with a revolver, and all the bad joojoo that issue brings was going to be corrected. Thankfully that question was partially answered by the well known Textron's patent for the operating mechanism, were they explore all sorts of solutions for this problem. The basic idea is to squeeze the case against the barrel so as to close the gap. Of all their solutions, the one that uses a bolt seems like the more reasonable one (the other ones involves a screw-on breech or a ratcheting mechanism...)

    US10641561-20200505-D00028.png

    The only issue left on this aspect is what sort of mechanism Textron is currently using... hope they win so we will know.

     

    If more people could shine a light into those finer details I would greatly appreciate their help.

     

    Stoner's Patent: https://patents.google.com/patent/US4770098A/en

    Textron's patents: https://patents.google.com/patent/US9267772

    And https://patents.google.com/patent/US9267772

     

     

  4. It's a shame that most useful gun files, including yours, have been yeeted from Grabcad... if it's not asking much it would be awesome if the F4 files were reuploaded, perhaps in a cloud or something like it.

     

    Regardless of that I would like to thank you Sturgeon for all of your work so, it has been a great inspiration for me, specially in regards to more aerodynamically efficient projectiles... so much so my final ME bachelor's project has been on the subject.

     

    You also inspired me to try to make my own rifles, if anything it's a great exercise in modeling and material selection, it also highlights what I need to improve. I hope I can post my work in another thread for it to be thoroughly shredded and I can beat the dumb out of the design and myself.

     

    Also... I cannot stress enough Sturgeon's points on charging handles and dust covers: Fuck those things.

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