DS 2 CPR Hyper Velocity Gun TL

[snrdg082102]

Morning all,

I have, until this morning, missed that hyper velocity guns are not available at tech level 5.

Which left me to figure out when a hyper velocity gun becomes available for in the Striker design sequence. My best guess after looking at the HEAP Penetration Modifiers and the CPR Ammunition tables is that hyper velocity guns are available at tech level 6.

Is my guess correct?

 

[shield]

yes

 

[snrdg082102]

Morning shield,

yes

Thanks for confirming that I guessed right that a Hyper velocity gun is available at TL 6. Good thing I haven't tried at test with a TL 5 hyper velocity gun.

 

[Timerover51]

The German Paris Gun in World War 1 was firing projectiles at a velocity in excess of 1 mile per second in 1918. The requirement for a hypervelocity gun is a perceived need, nitrocellulose (or equivalent) based propellant, and the ability to manufacture a very long, in proportion to caliber, gun barrel. The technology was available as of 1900, all that was needed was the need.

 

[snrdg082102]

Evening timerover51,

The German Paris Gun in World War 1 was firing projectiles at a velocity in excess of 1 mile per second in 1918. The requirement for a hypervelocity gun is a perceived need, nitrocellulose (or equivalent) based propellant, and the ability to manufacture a very long, in proportion to caliber, gun barrel. The technology was available as of 1900, all that was needed was the need.

Thank you for the history and I reminding about the gun, however per the Striker text on Book 3 page 13 hyper velocity guns are not available at TL 5.

The only other indication of hyper gun TL is in the HEAP Penetration and CPR Ammunition price tables which is TL 6.

When I get around to posting possible errata for the design sequences I think I am going to recommend a clarification to the wording for the hyper velocity gun TL.

Thanks again for reminding me about the Paris gun.

 

[Carlobrand]

Morning shield,



Thanks for confirming that I guessed right that a Hyper velocity gun is available at TL 6. Good thing I haven't tried at test with a TL 5 hyper velocity gun.

Most likely you'd have blown out the breech.

The German Paris Gun in World War 1 was firing projectiles at a velocity in excess of 1 mile per second in 1918. The requirement for a hypervelocity gun is a perceived need, nitrocellulose (or equivalent) based propellant, and the ability to manufacture a very long, in proportion to caliber, gun barrel. The technology was available as of 1900, all that was needed was the need.

The technology was not quite available - or perhaps it's more accurate to say it was in its infancy; the gun was ahead of its time. Each shot wore away some of the bore, so the shells were designed one slightly larger than the last, and numbered; the gunner had to fire them in the numbered order in order to maintain any degree of accuracy. After 65 rounds had been fired, the barrel was sent back to be rebored and a new set of shells - again numbered and each slightly larger than the one before it - made for the new bore.

They put one heck of a lot of effort and meticulous engineering into lobbing no more than 20 or so 8-9" bombs a day on Paris.

 

[snrdg082102]

Most likely you'd have blown out the breech.

I'd feel lucky if that was all, however the damage usually runs to blowing the breech, gun tube, and having all the ammunition go off.

 

[Timerover51]

Most likely you'd have blown out the breech.



The technology was not quite available - or perhaps it's more accurate to say it was in its infancy; the gun was ahead of its time. Each shot wore away some of the bore, so the shells were designed one slightly larger than the last, and numbered; the gunner had to fire them in the numbered order in order to maintain any degree of accuracy. After 65 rounds had been fired, the barrel was sent back to be rebored and a new set of shells - again numbered and each slightly larger than the one before it - made for the new bore.

They put one heck of a lot of effort and meticulous engineering into lobbing no more than 20 or so 8-9" bombs a day on Paris.

The barrel life expectancy of the Russian 115mm smoothbore was somewhere aroung 125 rounds or so. The life expectancy for the NATO 105mm gun, when firing full charge APDS/APFSDS/HEAT ammunition was a maximum of 400 rounds, but depending on conditions, could be considerably shorter. The life expectancy for the Abrams 120mm gun is classified, but I suspect that it is on the order of the 105mm, possibly less.

I fully understand about the Paris Gun bore erosion after every shot. The US 155mm Long Tom barrel was shot out after 1500 rounds, and the senior Ordnance Corps officer in France recommended that a new barrel be shipped with every 1500 rounds. The British 12"/50 caliber naval gun in World War 1 had an accurate barrel life expectancy of 125 rounds, with a magazine load of about 100 rounds. As soon as the barrel had fired 25 full-charge rounds, it should be replaced in order to allow for accurate firing of the full magazine. The US 16"/50 caliber gun on the Iowa-class, muzzle velocity of 2500 feet per second with a full charge and 2,700 pound AP projectile, had a barrel life expectancy of between 350 and 400 equivalent full-charge rounds. By getting really creative with additives, the Navy boosted that to 1500, by which time the barrel liner was so stretched that the gun could no longer fire accurately.

If you fire a hyper-velocity gun, you are going to rapidly erode the barrel, unless you work really hard with additives, and even then, you simply prolong accurate barrel life for a while. If you shoot rapid fire, your barrel erodes far faster, and then you have the problem of barrel droop, from severe overheating. I understand that this does not fit Striker rules, but that is the real world verses the fantasy one.

 

[Carlobrand]

The barrel life expectancy of the Russian 115mm smoothbore was somewhere aroung 125 rounds or so. The life expectancy for the NATO 105mm gun, when firing full charge APDS/APFSDS/HEAT ammunition was a maximum of 400 rounds, but depending on conditions, could be considerably shorter. The life expectancy for the Abrams 120mm gun is classified, but I suspect that it is on the order of the 105mm, possibly less.

I fully understand about the Paris Gun bore erosion after every shot. The US 155mm Long Tom barrel was shot out after 1500 rounds, and the senior Ordnance Corps officer in France recommended that a new barrel be shipped with every 1500 rounds. The British 12"/50 caliber naval gun in World War 1 had an accurate barrel life expectancy of 125 rounds, with a magazine load of about 100 rounds. As soon as the barrel had fired 25 full-charge rounds, it should be replaced in order to allow for accurate firing of the full magazine. The US 16"/50 caliber gun on the Iowa-class, muzzle velocity of 2500 feet per second with a full charge and 2,700 pound AP projectile, had a barrel life expectancy of between 350 and 400 equivalent full-charge rounds. By getting really creative with additives, the Navy boosted that to 1500, by which time the barrel liner was so stretched that the gun could no longer fire accurately.

If you fire a hyper-velocity gun, you are going to rapidly erode the barrel, unless you work really hard with additives, and even then, you simply prolong accurate barrel life for a while. If you shoot rapid fire, your barrel erodes far faster, and then you have the problem of barrel droop, from severe overheating. I understand that this does not fit Striker rules, but that is the real world verses the fantasy one.

Whether it does or does not fit Striker rules is moot. Striker's a tactical-level combat game with a few extra bells and whistles. Only thing it cares about is what happens when the lead starts flying. Any issues of barrel erosion or barrel droop - and likely a host of other issues - are quietly folded into vague rules about maintenance that occur away from the scene of battle, if one even feels like using maintenance (which actually makes for a very different game since it creates a practical consequence for all those nifty high-tech gadgets.)

Point is that the Paris gun represented the extreme limits of the technology of the era, a fascinating achievement but the fact there was only the one, and that it was only good for three or so days of service before needing to be rebored or replaced, and that it not only suffered erosion but suffered erosion at such a rate that it required each round to be sized up to deal with the erosion caused by the round immediately before it, with the result that the rounds needed to be fired in the precise numbered order, says it's about to an M-1 tank's gun what the Mercury capsule is to the Space Shuttle. It wasn't representative; it was for its time a cutting edge engineering solution that might possibly have laid the groundwork for better guns in later periods.