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After 23 days of drinking booze and random disappearing, judges finally picked winners of this competition!      In a 45 ton category we came to the conclusion that a member of this forum, w

Backstory (skip if you don't like alternate history junk)   The year is 2239. It has been roughly 210 years since the world was engulfed in nuclear war. Following the war, the United States

Best oscillating turret...

The turret now sports spaced high-hardness armor to shatter those pesky ultra-high velocity APCR rounds our engineers are convinced will be all the rage in the near future.
These are bolted and easily replaceable with, say, ERA arrays when it becomes available. The internal pockets have roof doors and are intended to hold small-arms ammo or ration boxes.
gu61CWa.png

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37 minutes ago, Toxn said:

Those pesky heavy tanks the Californians are developing, with their 89mm guns and 75mm of armour, are going to look real stupid now, huh?

Can you imagine what must go through the minds of tankers, raised their entire careers on the M6, when they first see the monstrosities we are cooking up?
And yes, we're basically skipping a generation and a half at least.

Also, think of the guys in the Deseret armored cars, barely proofed against fiddycal fire, having to go up against these beasts.

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28 minutes ago, N-L-M said:

Can you imagine what must go through the minds of tankers, raised their entire careers on the M6, when they first see the monstrosities we are cooking up?
And yes, we're basically skipping a generation and a half at least.

Indeed. I'm imagining dudes in the far East of the USSR jumping straight from BT tanks to T-55s.

 

"Wait, we're driving what now comrade?"

{a while later}

"No, it's just a shell Piotr. Not a bomb. No, we're not in the navy now."

{a bit after that}

"I know we could sling one of the old ones on the back and carry it around. No, command won't let us have 'sidearm tanks'."

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Just now, Toxn said:

Speaking of which: y'all know that this constant dick measuring about guns is going to bring up the spectre of the just making a damn T-55, right?

Mine started off as a product-improved T-55. Turns out if you tweak things and use more advanced tech than was available when the T-55 was developed, you can cram in a 145mm separate-loading gun.
This of course only popped up because @Sturgeon and I had a bit of an arms race.
The standard armament for me was and remains 105mm for now.

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20 minutes ago, N-L-M said:

Mine started off as a product-improved T-55. Turns out if you tweak things and use more advanced tech than was available when the T-55 was developed, you can cram in a 145mm separate-loading gun.
This of course only popped up because @Sturgeon and I had a bit of an arms race.
The standard armament for me was and remains 105mm for now.

Yeah, bowl turrets haven't aged as well as everything else.

 

Still, you could submit a T-55 all on it's lonesome and comfortably beat all the requirements for this contest.

 

Edit: most importantly, a T-55 had about the best possible chance of being produceable by a post-apocalyptic industrial civilisation. Which is an argument you're going to have a harder time making for some of the entries.

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Just had a (possible) revelation in regards to my gun: Since it is a squeeze bore, wouldn't the shell increase in velocity proportionally with the decrease in diameter? Or am I misremembering how that works? 

 

Spoiler

Lets say I want my shell to go 1200m/s once it leaves the barrel. well the difference in the surface area between the 94mm and 74mm sections is: 

 

π942 = 27,759.11 cm2

π742 = 17,203.36 cm

 

17,203.36 cm2 / 27,759.11 cm2 = 0.62 

 

1200m/s x 0.62 = 744m/s 

 

So I would only have to calculate how much propellant I need to accelerate my projectile to 744m/s. 

 

If I'm dead wrong, please tell me. 

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It wouldn't - the benefit is the reduced cross-section reducing the drag.

 

Technically the propellant gases will still accelerate the projectile through the conical bit, but as the diameter (and area at the base of the projectile reduce) then the force applied by the gases also reduces (the energy taken to crush the skirts also slows it down) - so muzzle velocity for a squeezebore is lower than for a straight walled tube of equal length. To model one in the powley computer I'd be tempted to adjust the barrel length for constant swept volume (i.e. starting diameter * length input to powley computer = (starting diameter * length of straight bit of barrel) + (volume of conical bit of barrel)), the swaging losses are probably pretty small.

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12 minutes ago, Lord_James said:

Just had a (possible) revelation in regards to my gun: Since it is a squeeze bore, wouldn't the shell increase in velocity proportionally with the decrease in diameter? Or am I misremembering how that works? 

 

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Lets say I want my shell to go 1200m/s once it leaves the barrel. well the difference in the surface area between the 94mm and 74mm sections is: 

 

π942 = 27,759.11 cm2

π742 = 17,203.36 cm

 

17,203.36 cm2 / 27,759.11 cm2 = 0.62 

 

1200m/s x 0.62 = 744m/s 

 

So I would only have to calculate how much propellant I need to accelerate my projectile to 744m/s. 

 

If I'm dead wrong, please tell me. 

 

No. To estimate velocity, find the bore area. Then you need to find the virtual bore diameter and use that in Powley. Virtual bore diameter will be the diameter that gives you an equivalent bore area for how long your barrel is.

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6 minutes ago, Xlucine said:

It wouldn't - the benefit is the reduced cross-section reducing the drag.

 

Technically the propellant gases will still accelerate the projectile through the conical bit, but as the diameter (and area at the base of the projectile reduce) then the force applied by the gases also reduces (the energy taken to crush the skirts also slows it down) - so muzzle velocity for a squeezebore is lower than for a straight walled tube of equal length. To model one in the powley computer I'd be tempted to adjust the barrel length for constant swept volume (i.e. starting diameter * length input to powley computer = (starting diameter * length of straight bit of barrel) + (volume of conical bit of barrel)), the swaging losses are probably pretty small.

 

Xlucine speaks the truth.  The squeeze in a squeezebore is just to mash the skirt into a less draggy configuration.

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In pains me that I probably won't be able to throw my hat in the ring. But in case I get the chance, I have a few questions:

What is the average height of a conscript male?
What fuel does the enemy use?
Is the technology cut-off date 1969?
Is cast armor roughly 15% weaker?


 

 

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44 minutes ago, Xoon said:

In pains me that I probably won't be able to throw my hat in the ring. But in case I get the chance, I have a few questions:

What is the average height of a conscript male?
What fuel does the enemy use?
Is the technology cut-off date 1969?
Is cast armor roughly 15% weaker?


 

 

 

Average male conscript height is about 5 foot 8 (~1.72m).

Enemy uses both diesel and gasoline.

Technology cutoff date is about 1950, although it's not a hard date since modern knowledge is available.

No, assuming the castings are done well.

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      Supplementary Out of Canon Information:
       
       
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