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StrixKitty

Burst Charge Data for the 105mm/65-caliber SK C/33?

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Question is the title. Any info? Nothing found on NavWeaps. I am able to assume based on the dimensions of the SK C/32 that the projectiles of the two are very similar and otherwise the same, unless proved different.

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For the 10.5 cm SK C/33 gun, the shell 15.1kg and the bursting charge 5.02kg. Source is M.J. Whitley's German Capital Ships of World War II, page 217.

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3 hours ago, GrandAdmiral_2016 said:

For the 10.5 cm SK C/33 gun, the shell 15.1kg and the bursting charge 5.02kg. Source is M.J. Whitley's German Capital Ships of World War II, page 217.

That's impossible; you likely have the propellant charge - not the burst (powder in the projectile). 11 pounds of charge would outstrip a 128/45 and 61-cal as well as any USN 5" gun. Actually, I'm sure it beats most 6" guns. Be aware that this is the same weight of projectile as the 105/45-cal SK C/32 with a 3.2 pd burst...

Edited by StrixKitty

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49 minutes ago, StrixKitty said:

That's impossible; you likely have the propellant charge - not the burst (powder in the projectile). 11 pounds of charge would outstrip a 128/45 and 61-cal as well as any USN 5" gun. Actually, I'm sure it beats most 6" guns. Be aware that this is the same weight of projectile as the 105/45-cal SK C/32 with a 3.2 pd burst...

All it says for probable burster is Fp02, which makes it a 1.67kg burster as far as I can figure it. That makes it a 3.6lb burster, which makes more sense. The SK C/32 is 45 calibers long, the SK C/33 is 65 calibers long, a difference of 21 cm in barrel length, plus there is a difference of 120m/sec in muzzle velocity between the two guns in favor of the later model. I stand corrected.

 

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On 10/20/2017 at 3:53 PM, GrandAdmiral_2016 said:

All it says for probable burster is Fp02, which makes it a 1.67kg burster as far as I can figure it. That makes it a 3.6lb burster, which makes more sense. The SK C/32 is 45 calibers long, the SK C/33 is 65 calibers long, a difference of 21 cm in barrel length, plus there is a difference of 120m/sec in muzzle velocity between the two guns in favor of the later model. I stand corrected.

 

Actually, I would too find this correct. I meant to type 3.6 pds, The thing is, as I went through NavWeaps again, that the 105/45 and 105/65 both have the exact same projectile. Their weights and lengths are the same. In fact, I'd go so far as to say that the Germans used the same projectile between the two just as a means to simplify production, and the 105/65 being a simple improvement in ballistics, propellant charge, and overall accuracy compared to the 105/45, not as a means to be a heavier hitting gun where burst is concerned. 

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At that caliber you don't want a charge exploding in the tube, and that is about as large a bursting charge you can put in a shell that size while avoiding problems of having it cook off in the tube. The chamber pressures are very high, as are the gas temperatures. I have fired 81mm and 4.1-inch mortars with larger bursting charges, but the muzzle velocity and tube pressures and temperatures in a mortar are much lower than those of an artillery piece of any type of the same caliber. Look up the charge size for a modern 105mm light field howitzer. That will give you a baseline comparison. The 65-caliber gun was an excellent heavy AA gun on land. Just ask the 8th Air Force and RAF Bomber Command veterans!

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On 10/23/2017 at 0:14 PM, GrandAdmiral_2016 said:

At that caliber you don't want a charge exploding in the tube, and that is about as large a bursting charge you can put in a shell that size while avoiding problems of having it cook off in the tube. The chamber pressures are very high, as are the gas temperatures. I have fired 81mm and 4.1-inch mortars with larger bursting charges, but the muzzle velocity and tube pressures and temperatures in a mortar are much lower than those of an artillery piece of any type of the same caliber. Look up the charge size for a modern 105mm light field howitzer. That will give you a baseline comparison. The 65-caliber gun was an excellent heavy AA gun on land. Just ask the 8th Air Force and RAF Bomber Command veterans!

Ah, I see. You trade one for the other. The other option is to reconfigure the entire 105mm gun to accept a larger shell with a larger burst charge. Thx. 

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25 minutes ago, StrixKitty said:

Ah, I see. You trade one for the other. The other option is to reconfigure the entire 105mm gun to accept a larger shell with a larger burst charge. Thx. 

Exactly. while the gun may have similar specs to the old one once redesigned, the firing chamber, breach blocks, and gun barrel will have been constructed to a higher standard, with slightly thicker barrels and better steel in the components capable of handling the higher stresses impiicit with a redesigned shell, powder charge and muzzle velocity. In most cases the redisgned gun is heavier, and the recoil systems are also heavier. It all depend on what you want the gun to do, seaborne surface direct fire, AA fire, anti-tank fire, and indirect artilley fire can all be done with the same gun if it is built for it. The German 88mm Flak and 105mm Flak guns are excellent examples of this-multi-role capability built in. The Ansaldo 90mm AA gun was an excellent anti-tank and direct fire weapon for assault gun mounting. All three Italian services used it.

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6 hours ago, GrandAdmiral_2016 said:

Exactly. while the gun may have similar specs to the old one once redesigned, the firing chamber, breach blocks, and gun barrel will have been constructed to a higher standard, with slightly thicker barrels and better steel in the components capable of handling the higher stresses impiicit with a redesigned shell, powder charge and muzzle velocity. In most cases the redisgned gun is heavier, and the recoil systems are also heavier. It all depend on what you want the gun to do, seaborne surface direct fire, AA fire, anti-tank fire, and indirect artilley fire can all be done with the same gun if it is built for it. The German 88mm Flak and 105mm Flak guns are excellent examples of this-multi-role capability built in. The Ansaldo 90mm AA gun was an excellent anti-tank and direct fire weapon for assault gun mounting. All three Italian services used it.

You appear very knowledgeable in the fine art of weapon construction. Tell me, because I am genuinely curious, what would happen if I created a 105mm/66-caliber (barrel, bore, and rifling extended accordingly - rifling to 0.5m of the bore) SK C/33-type with a 62 pd total weight, 4 pd burst, and (other stats I have somewhere but can't remember at the moment - suffice to say the projectile only is longer and the 13.34 prop is the same) as well as chrome rifling to 0.020mm (0.005 more than the 127/38-cal had), a vertical wedge sliding breechblock, and uniform RH 1 in 28 (Japanese-style) and decreasing grooves from 1.5mm by 6.4mm down to 1mm by 5.5mm as it grows closer to the end of the gun. Also, what of the implementation of a squeeze bore?

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You are speaking about a QF naval rifle with high muzzle velocity and a flat trajectory, similar to a Vickers 105mm main battle tank gun which I am familiar with, having cross-trained in armor (I was, a very long time ago, in the infantry as a young adult). That particular gun was originally designed for AA work. 62 lbs fixed ammuntion is about as heavy as a single loader can handle in a cramped tank turret or as a free standing artillery piece. The human limitation is the key at this caliber. Separate shell and powder is easier to handle, but you end up with a slower rate of fire without power assist. The RN trialed a heavier fixed shell of 64 lbs at 4.7-inches and found that it did not work well in practice with hand loading in a seaway, so they stuck with the 50lb shell for the whole war. 

A squeeze bore was put in service as an anti-tank gun late in the war by the Wermacht. It was difficult to manufacture and to maintain, but worked quite well against Shermans, which the German landsers called Ronsons, for the way they burned, and was effective against T34s as well at close range. More recent metallurgical and propelllant technology makes this viable now, but the hi-tech thing being done now is magnetic rail guns for over the horizon long range rapid fire with terminal shell guidance, or high velocity kinetic penetration, at sea or on land. The concept has been tested extensively by the USN and the US Army. It requires 300 to 600 megawatts of electrical power for larger calibers, which means a large powerplant in a large ship. Zumwalt-class DD guns...destroyers as large as heavy cruisers...and a whole lot more expensive....and on land still too big to put in a tank turret.

The RN alway favored hand-loaded guns for simplicity and speed of loading at calibers up to 6-inch. They came late to the party with RPC, compared to the USN and other navies  While I was a teenager, I was a sea cadet and we got to drill on the RN 4-inch Mk XIX twin turret. A well drillled gun crew could reach 16 to 18 rounds per minute from both barrels and sustain it for about 3 minutes, double the standard quoted ROF. After that the lactic acid catches up with you and the ROF drops to about two-thirds of that, 8 to 10 rounds per minute. Later naval turrets have remote power control and power hydraulic ramming, which minimizes physical effort but imposes a machine regulated maximum ROF.

If you really want to maximize hitting power against surface targets at this caliber, a breach loader with separate shell and cartridge is a better bet as you can up the ante with slightly heavier shells and bursting charges, while accepting degraded AP performance due to slighly lower muzzle velocities with the same breach charge weight of propellant. It is all about kinetic energy at impact with AP ammuntion, even at sea. Depends on how you define it.

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14 hours ago, GrandAdmiral_2016 said:

You are speaking about a QF naval rifle with high muzzle velocity and a flat trajectory, similar to a Vickers 105mm main battle tank gun which I am familiar with, having cross-trained in armor (I was, a very long time ago, in the infantry as a young adult). That particular gun was originally designed for AA work. 62 lbs fixed ammuntion is about as heavy as a single loader can handle in a cramped tank turret or as a free standing artillery piece. The human limitation is the key at this caliber. Separate shell and powder is easier to handle, but you end up with a slower rate of fire without power assist. The RN trialed a heavier fixed shell of 64 lbs at 4.7-inches and found that it did not work well in practice with hand loading in a seaway, so they stuck with the 50lb shell for the whole war. 

A squeeze bore was put in service as an anti-tank gun late in the war by the Wermacht. It was difficult to manufacture and to maintain, but worked quite well against Shermans, which the German landsers called Ronsons, for the way they burned, and was effective against T34s as well at close range. More recent metallurgical and propelllant technology makes this viable now, but the hi-tech thing being done now is magnetic rail guns for over the horizon long range rapid fire with terminal shell guidance, or high velocity kinetic penetration, at sea or on land. The concept has been tested extensively by the USN and the US Army. It requires 300 to 600 megawatts of electrical power for larger calibers, which means a large powerplant in a large ship. Zumwalt-class DD guns...destroyers as large as heavy cruisers...and a whole lot more expensive....and on land still too big to put in a tank turret.

The RN alway favored hand-loaded guns for simplicity and speed of loading at calibers up to 6-inch. They came late to the party with RPC, compared to the USN and other navies  While I was a teenager, I was a sea cadet and we got to drill on the RN 4-inch Mk XIX twin turret. A well drillled gun crew could reach 16 to 18 rounds per minute from both barrels and sustain it for about 3 minutes, double the standard quoted ROF. After that the lactic acid catches up with you and the ROF drops to about two-thirds of that, 8 to 10 rounds per minute. Later naval turrets have remote power control and power hydraulic ramming, which minimizes physical effort but imposes a machine regulated maximum ROF.

If you really want to maximize hitting power against surface targets at this caliber, a breach loader with separate shell and cartridge is a better bet as you can up the ante with slightly heavier shells and bursting charges, while accepting degraded AP performance due to slighly lower muzzle velocities with the same breach charge weight of propellant. It is all about kinetic energy at impact with AP ammuntion, even at sea. Depends on how you define it.

So, you suggest divided ammunition. How should the projectile and cartridge come together?

 

Also, I did think of a ERG but decided that conventional weaponry was good for me. 

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In exactly the same manner as on a USN 5/38 or a 105mm howitzer, separate shell and base fused cartridge case for smaller calibers like a 105mm, shell into breech first, cartridge second, rammed home, close breachblock, ready for firing. The limitation with this is most older guns had a maximum elevation that allow shell and charged cartridge case to be loaded, which slows down the ROF at high elevations. In modern ships this is overcome using powered loading systems strong enough to load the gun at any angle of train and elevation. Modern systems are mostly fully automated throughout the firing cycle without anyone in the turret except to fix a problem if one occurs. In this day and age it is a relatively simple design issue. Gun caliber must be decided in the initial design phase by what the ship size is and what you want to do with a gun system to ensure adequate power for the turret/gun/loading systems and fire control. Having a dual type system where humans can operate the gun in the event of failure or systems damage is considered a luxury in this day and age, because of the necessity for a larger crew aboard ship which increases life cycle operating costs and ship size (habitable volume increase means higher construction costs). The jury is still out on this one.

Damage control (fire supression for the most part, with some pumping and flooding control systems) has also been automated as much as possible to decrease crew size in many modern warships, especially in smaller navies and on smaller ships like GP frigates, corvettes, littoral combat vessels, and logistics support ships. IMHO, fully automated systems will bite you in the butt in combat where you lack adequate human resources to handle it the old-fashioned way. Only the USN has made allowances for this with its' newer ships with automated systems, and can afford higher crewing levels, at least for the time being. Lack of real money is going to affect military budgets in the US, which has been at war with half the planet for 16 years. The current USN policies won't last if they ever face a real capable opponent at sea.

Adapt and overcome as the USN has sucessfully done in the past, and may face in the future,  may not work in a come-as-you-are war. Historically, warfare has alway been asymmetrical in nature. Great power wars were rare, and global conflicts are mostly a 20th century phenom. In such a situation, your fleet may be ill-adapted to the threat. The RN faced this in 1940. That is where the USN is at present.

The RN learned the hard way in the Falklands what the limitations with automated gun and missile control were like, and that their WW II damage control lessons had been unlearned. They paid a high price for it. Despite that, they have followed other small navies down the automation path for economic reasons. IMHO it is a bad decision.

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1 hour ago, GrandAdmiral_2016 said:

In exactly the same manner as on a USN 5/38 or a 105mm howitzer, separate shell and base fused cartridge case for smaller calibers like a 105mm, shell into breech first, cartridge second, rammed home, close breachblock, ready for firing. The limitation with this is most older guns had a maximum elevation that allow shell and charged cartridge case to be loaded, which slows down the ROF at high elevations. In modern ships this is overcome using powered loading systems strong enough to load the gun at any angle of train and elevation. Modern systems are mostly fully automated throughout the firing cycle without anyone in the turret except to fix a problem if one occurs. In this day and age it is a relatively simple design issue. Gun caliber must be decided in the initial design phase by what the ship size is and what you want to do with a gun system to ensure adequate power for the turret/gun/loading systems and fire control. Having a dual type system where humans can operate the gun in the event of failure or systems damage is considered a luxury in this day and age, because of the necessity for a larger crew aboard ship which increases life cycle operating costs and ship size (habitable volume increase means higher construction costs). The jury is still out on this one.

Damage control (fire supression for the most part, with some pumping and flooding control systems) has also been automated as much as possible to decrease crew size in many modern warships, especially in smaller navies and on smaller ships like GP frigates, corvettes, littoral combat vessels, and logistics support ships. IMHO, fully automated systems will bite you in the butt in combat where you lack adequate human resources to handle it the old-fashioned way. Only the USN has made allowances for this with its' newer ships with automated systems, and can afford higher crewing levels, at least for the time being. Lack of real money is going to affect military budgets in the US, which has been at war with half the planet for 16 years. The current USN policies won't last if they ever face a real capable opponent at sea.

Adapt and overcome as the USN has sucessfully done in the past, and may face in the future,  may not work in a come-as-you-are war. Historically, warfare has alway been asymmetrical in nature. Great power wars were rare, and global conflicts are mostly a 20th century phenom. In such a situation, your fleet may be ill-adapted to the threat. The RN faced this in 1940. That is where the USN is at present.

The RN learned the hard way in the Falklands what the limitations with automated gun and missile control were like, and that their WW II damage control lessons had been unlearned. They paid a high price for it. Despite that, they have followed other small navies down the automation path for economic reasons. IMHO it is a bad decision.

What keeps the projectile from going further down the barrel when the cartridge is inserted; rammed behind it?

 

Also, I would too opt for a dual-system. Power-ramming and no-crew turrets being a sort-of luxury, with the gun firer being in the CIC operating from a camera, but also having the space within the turret to crew it in a situation that requires a more manual approach.

 

Another thing, what, in your opinion, is the best dual turret for under 140mm guns? (WW2 or close era) Especially for smaller lightweight boats who are looking for a weatherproof mount. 

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