-  [WT]  [Home] [Manage]

[Return] [Entire Thread] [Last 50 posts]
Posting mode: Reply
Subject   (reply to 108967)
File URL
Embed   Help
Password  (for post and file deletion)
  • Supported file types are: GIF, JPG, PNG, WEBM
  • Maximum file size allowed is 5120 KB.
  • Images greater than 300x300 pixels will be thumbnailed.
  • Currently 1114 unique user posts. View catalog

  • Blotter updated: 2017-02-04 Show/Hide Show All

Patches and Stickers for sale here

File 15609158738.png - (67.97KB , 914x410 , Picture1-914x410.png )
108967 No. 108967 ID: 6affc4
Check this out, what do you think, guys?
Maybe cobalt-alloy barrels are actually coming.

Apparently our weaponmakers are also working on it https://foxtrotalpha.jalopnik.com/this-russian-company-plans-a-sniper-rifle-that-can-fire-1829496377

Also, wouldn't it be great to have a squeezebore high velocity pistol. It can be smoothbore too given the ranges pistols are normally used at, so cheaper and with higher barrel life.
Expand all images
>> No. 108972 ID: a067fa
So its effectively a modern take on the squeeze bore? Neat.
Barrel wear will still be an issue, but hopefully modern metallurgy can overcome some of what 30's germany could not. The collet extractor design is a good approach in this use case, but I can't help but think that any grime or dirt getting in there is going to cause major issues with seating it correctly.
>> No. 108978 ID: b6e91c
>The cartridge would not use gunpowder but instead “detonating chemicals of a special composition”—whatever that is.

>> No. 108979 ID: d9f7f4
File 156107623847.png - (30.87KB , 1944x982 , US X artillery liquid propellant weapon system 1.png )
I remember reading about experimental artillery using combustible liquid injected behind the shell in the breech instead of gunpowder bags, but it did not work out well.

Bulk loaded liquid propellants are an artillery technology that was pursued at the U.S. Army Research Laboratory and U.S. Naval Weapons Center from the 1950s through the 1990s. The advantages would be simpler guns and a wider range of tactical and logistic options. Better accuracy and tactical flexibility would theoretically come from standard shells with varying propellant loads, and logistic simplification by eliminating varying powder loads.
In general, BLP guns have proven to be unsafe to operate, and they have never entered service.
In general, hydrodynamic effects make the ignition process unpredictable. Bubbles can form in uncontrolled ways, causing varying surface areas and therefore varying pressure profiles. The result can be widely varying pressures in the breech and tube that cause unexpected gun stresses and safety problems. Most programs have reported failures, some spectacular, with each failure generally ending the program that had it. https://en.wikipedia.org/wiki/Bulk_loaded_liquid_propellants
>> No. 108980 ID: 5ddd04
File 15610776317.jpg - (30.00KB , 564x500 , German WW2 Panzerbuchse 41 'squeeze bore'.jpg )
German WW2 Panzerbuchse 41 'squeeze bore' anti-tank gun that uses a barrel that chokes down to a tighter diameter at the muzzle and shells with crushable driving bands that can go down that barrel to maximize the gas pressure behind it.

The design was based on a cone-shaped barrel, with the caliber reducing from 28 mm at the chamber end to only 20 mm at the muzzle. The projectile carried two external flanges; as it proceeded toward the muzzle, the flanges were squeezed down, decreasing the diameter with the result that pressure did not drop off as quickly and the projectile was propelled to a higher velocity. The barrel construction resulted in a very high muzzle velocity - up to 1,400 m/s. https://www.reddit.com/r/MilitaryPorn/comments/2mzpdj/28_cm_schwere_panzerb%C3%BCchse_41_squeeze_bore_gun/
>> No. 108981 ID: 5ddd04
File 156107777992.jpg - (192.17KB , 1280x778 , German WW2 Panzerbuchse 41 (2_8cm PzB41) 28-20mm G.jpg )
German WW2 Panzerbuchse 41 (2.8cm PzB41) 28-20mm Gerlich tapered bore gun.
4.2 cm Pak 41 and 7.5 cm PaK 41 – Other German anti-tank guns working on the squeeze bore principle.
>> No. 108982 ID: 48ddd0
File 156107796664.jpg - (17.45KB , 288x461 , German WW2 Panzerbuchse 41 (2_8cm PzB41) 28-20mm G.jpg )
>> No. 108983 ID: 48ddd0
File 156107801486.jpg - (67.62KB , 800x533 , German WW2 Panzerbuchse 41 sPzB 41, pierces 75mm a.jpg )
>> No. 108984 ID: 48ddd0
File 156107835562.jpg - (394.36KB , 3104x752 , UK WW2 40mm QF 2-pounder Littlejohn adaptor squeez.jpg )
The Littlejohn adaptor was a device that could be added to the British QF 2 pounder (40 mm) anti-tank gun. It was used to extend the service life of the 2-pounder during the Second World War by converting it to squeeze bore operation. "Littlejohn" came from the literal anglicization of the name of František Janeček, the Czech designer and factory owner who had been working on the squeeze-bore principle in the 1930s and his son František Karel Janeček, who had brought his know-how to Britain after fleeing from German-occupied Czechoslovakia.
The adaptor took the form of a reducing bore that was screwed on to the end of the gun. This was coupled with a round formed from a hard core (tungsten) inside a softer metal casing - the armour-piercing, composite non-rigid (APCNR) design.
Upon firing, the round travelled the first part of the bore as normal, but on entering the tapering portion the softer and malleable metal of the outer shell of the round was compressed - from 40 mm to approximately 30 mm.
When the round emerged from the adaptor, it now had a smaller cross-section than before. Together with the higher driving pressure developed in a barrel of diminishing cross-section compared to a standard cylindrical bore, the APCNR round, called APSV (from armour-piercing super velocity), travelled faster, over a flatter trajectory. The Littlejohn adaptor/APCNR combination gave the 2 pounder a similar effect as the APDS round used with the much larger and heavier QF 6 pounder gun.
The muzzle velocity of the APSV Mark II shell was 1,143 m/s compared with the 792 m/s of the normal 1.2 kg APCBC shell. The lighter Mark I APSV shell was capable of penetrating 88 mm of armour at 450 m at a 30-degree angle of impact.
In 1942, US Ordnance tested the Littlejohn adaptor in an attempt to develop a taper bore adaptor for the 37 mm Gun M3. The adaptor distorted after a few shots. https://en.wikipedia.org/wiki/Littlejohn_adaptor
>> No. 108985 ID: c917a1
File 156107846031.jpg - (66.92KB , 800x639 , UK WW2 40mm QF 2-pounder Littlejohn adaptor on Mk .jpg )
Light tank Mk VII Tetrarch Mk I with Littlejohn adaptor.
The adaptor was chiefly used on British armoured cars, e.g. the Daimler, which had been designed and built earlier in the war and could not be readily fitted with a larger gun. As an adaptor to the existing gun it could be removed so that normal rounds could be fired. This offered increased anti-armour effect but with obvious drawbacks in combat conditions. When crews discovered the special 'squeeze bore' ammunition was more effective than the standard 2pdr AT round even when not 'squeezed', the usual practice was to store the adaptors rather than have them fitted.

It was also experimentally fitted to the Vickers 40mm S Gun fitted to the Hawker Hurricane IID anti-armour variant. As Anthony G Williams concludes in The Cartridge Researcher, the official bulletin of the European Cartridge Research Association (February 1999): the gun/ammunition combination did not function with sufficient reliability.

The article goes on to state: Tests in the Far East showed a high level of accuracy, with an average of 25% of shots fired at tanks striking the target [but] attacks with HE were twice as accurate as with AP, possibly because the ballistics were a closer match to the .303 in (7.7 mm) Browning machine guns used for sighting
>> No. 108987 ID: bbee29
File 156108553088.jpg - (4.45MB , 3256x4264 , casull.jpg )
More than the obvious issues that can arise from the collet chamber, I think there's a lot of problems here, stuff that I don't really see mentioned in the article.

>muzzle flash
>heat/sustained shooting
>case failure
>expenses (there are many at play here)

For case failure, you can have a breech (misspelled as "breach" in the article lol) strong enough and a fancy collet to unstick the case but I don't know how well it can hold up if the case itself can fail in a variety of ways. Your fancy new gun might not enjoy a loose primer jammed into the collet or bits of melted/deformed case material flying around inside this space magic gun. If they're using a new type of case, we then have even more expense because it's not just different/more powder in an existing caliber but a whole new case for it. To reliably deal with +100ksi, you probably have to do something like what Casull did with his high velocity builds, pic related.

Furthermore, Casull also deals with fast barrel erosion by simplifying and making the barrel changing process faster and easier. Instead of making a stupid expensive and hard to make tapered bore cobalt unicorn sorcery barrel, buy a few barrel blanks for pocket change and swap them out when they're cooked. He basically designs the action around a barrel that will only last a few hundred rounds and thus makes the chamber part of the action, so no chamber reaming is needed.

I also see that the bolt in this "invention" has to rotate for quite a bit before unlocking. Perhaps they want this to limit fire rate, that does make sense. With the bolt requiring what looks like a full 360 degree rotation to unlock, your full auto won't be a buzzsaw. However, is that going to be reliable? Most gas guns have a short rotation because the gun only has pressure for a short time, and it has to then have enough energy to drive the action after this unlocking has finished. Usually, the bolt rotation is done while the carrier is basically at full speed, so there's not much time or energy spent on actually opening the bolt (ar-15, IIRC, open in 22.5 degrees). The pitch of that bolt and bolt carrier cam groove tells me that there's going to be a lot of time spent spinning the bolt open. I hope by the time that the bolt has unlocked, I hope there's still something left in inertia or gas pressure or recoil energy (if it's recoil operated) to cycle the gun.

I would have went with a stepped breech or stepped threads or something like that, again, a bit more like Casull or just most big guns that have to deal with crazy bolt thrust as area squares so that big breech face is going to be pushing pretty damn hard. This type of locking system can be made to open in a very short rotation despite being capable of taking ridiculous pressure and bolt thrust every day forever.

This is still cool and I'd love to shoot that sort of gun like in GitS movie but from what I can see it's an engineer that hasn't done his history homework and is inventing something that's already been tried a couple times. Sadly, I think this will fizzle out and we won't hear from that company again.
>> No. 109034 ID: 6affc4
I think the the emphasis is that it's detonating and not deflagrating.

Bulk loading aside, what happens if you use semi-solid substances for density and uniformity of the propellant. Say, if you had a propellant that's like wax or grease.
Also, why do they make solid gunpowder in tiny pellets instead of one giant pellet of the necessary mass that would fit snug in the case?
>> No. 109036 ID: e56201
> Also, why do they make solid gunpowder in tiny pellets instead of one giant pellet of the necessary mass that would fit snug in the case?

Surface area. Also, you would need a different pellet for every load size, and probably some different ones of the same load for different cartridges.
>> No. 109037 ID: e56201
>With the bolt requiring what looks like a full 360 degree rotation to unlock,...

Plus that carrier looks like it has a hell of a weak spot between the start and end of the cam groove.
>> No. 109073 ID: b2b3ad
But surface area increases as the pellet burns if it's cylindrical and is burned from inside.
>> No. 109074 ID: b2b3ad
But surface area increases as the pellet burns if it's cylindrical and is burned from inside.
>> No. 109079 ID: e56201
Still not as much surface area as normal granules. Really, why would they make it the way you're suggesting? What's the advantage?
>> No. 109080 ID: b2b3ad
More powder in the same volume, convenient to reload.
>> No. 109086 ID: e56201
It's only convenient to reload if you're only loading one bullet weight in one cartridge. It's less convenient when you have to buy a different pellet for every cartridge and powder charge. How would you even work up a load, buy a whole pack of pellets in every increment just to test a few? And you'd basically have to abandon bottleneck cartridges. And it would still burn slower due to surface area.
>> No. 109087 ID: 6affc4
I dunno, it seems like a great option for handloading, instead of having to load with a scale you just stick the right pellet and do he rest. And isn't slow burning powder beneficial for many loads? As for bottleneck cartridges, i thought you open the case up before reloading anyway, if you don't, then yeah, it's not worth it of course.
>> No. 109257 ID: 6affc4
Now that I think about it, some people still hunt with percussion revolvers. One could make a replica for smokeless powder that in pellets will be easy and safe to load into the cylinder.
>> No. 109266 ID: bbee29
>hypervelocity bby
k so I'm fucking drunk as hell, but I've been thinking of a light gas gun using a straight cased 50 BMG and a 2" .224 BR barrel blank. Might require some gain-twist magic for accuracy though. So how long should the piston portion of this light gas gun be? If it's too short, we waste power, if it's too long, we waste power. What should the final angle of the taper in the straight-cased 50bmg piston chamber be? It'll be tapering down an HDPE piston tip to get max pressure so that angle might be important.

fuck I'm trying to get all the speeds and get a VLD .223 boolet going faster than it ever wants to go but I can't seem to figure out how many hydrogens can fit in ~18k joules of useful energy from this shit to pop that valve. I can't even get any external ballistics predictions because nobody really knows what happens when a 90gr .224 berger is going at sanic overblown themesong speaker speed. For simplicty, we have 4000 bar max pressure pushign a piston that's approximately 20mm in diameter, with the compressible side being 200 bar of hydrogen. How much of this hydrogern can we compress before the piston comes to a stop?

I remember that guy from /t/ saying he was an engineer student or some shit so he should plug in those numbers in his big enginner brain and get me some approximate numbers becuase I'm ready with them steel cutting tools like fuck I can make this shit just get me some guesstimates you lads will see some shit
>> No. 109267 ID: 793056
File 157374131578.jpg - (255.71KB , 600x592 , what in tarnation.jpg )
Sir this is a Wendy's

That sounds like some mad barrel burning shit.
>> No. 109268 ID: 6fe1bd
Lol that wasn't my most coherent post, I'll admit. Later this weekend I'll post pics for some CAD stuff I've been poking at to clear up that mess.

Nice thing about the design is that it only requires threads for the coupler to the burst disc valve and a throat for the bullet, so there's practically no machining involved with swapping barrels.
[Return] [Entire Thread] [Last 50 posts]

Delete post []
Report post