TNE FF&S Hypervelocity Smoothbore guns

[snrdg082102]

Morning Piper,

Don't be sorry you have to remember that you are dealing with a broke down old USN submarine sailor who is missing a couple of cards in his deck. However, I've kept all the jokers.

Actually you have helped clear up the mess I created in my own mind and I don't feel that this little side tangent is in error in fact Traveller's design sequences are pretty good in my opinion.

Thanks again for the help

I think I understand where you're coming from.

Because the terms "rifled", "smoothbore" and "hypervelocity" appear in the text (and actually within the design sequence on p. 108, D1) you feel that some stage in the design sequence should define this. This isn't unreasonable, but there is nothing in the design sequence or the published errata that I've found that clears this up.

Personally, I don't believe that this is an error. It's my opinion that the "magic" that occurs at TL7+ isn't due to whether or not a gun is rifled or what the actual muzzle velocity is. It's due to the introduction and general use of FSDS ammunition, specifically the ability to mass produce long rod KE pentrators from extremely hard and/or dense materials. But then, there's nothing in the design sequence that actually states this, either.

I'm really sorry I couldn't clear this up for you, Tom.

 

[Vladika]

Rifled vs Smooth bore

Rifled gun barrels are practically never used in modern artillery and particularly direct fire guns. Fin stabilized munitions are FAR more accurate and can NOT be fired from a riffled barrel. (SOME exceptions CAN occur such as discarding sabot rounds)

HE and associated rounds do NOT penetrate anywhere near as well if spinning. It interferes with the formation of the gas jet.

In annual NATO tank firing competitions the British NEVER win. Reason: They are the only member nation using rifled tank barrels. (This may have changed, I've been out of the loop for awhile.) Note they don't use HE or HEAT rounds but a HESH (High Explosive Squash Head) round. It forms not a jet but spreads out and "spalls" off armor from the interior. US M728 Combat Engineer Vehicle uses the same type round and in a smooth bore. (It is not a tank, though it looks like one.)

Also, a mussel break can NOT be used with fin stabilized munitions. This is important for howitzers. In a true mortar, loaded from the tube end, a smooth bore is essential for the round to slide down the tube and hit the firing pin with enough force to fire.

In a long range gun, riffling WILL burn away very rapidly, forcing constant changes in many range calculations (hard without a computer and vast quantities of trial DATA) and frequent (Expensive) barrel replacement.

These "Rules" are nearly universal. You, and I, can find exceptions due to hardheadedness or very unusual circumstances of designs.

Traditionally, the longer the barrel, the greater the muzzle velocity. The greater the muzzle velocity, the greater the penetration of kinetic energy rounds. Energy=½ mv². From the equation it is easily seen the velocity is the controlling factor. Longer barrels are lighter than the vastly heavier breaches needed to achieve the same, or close, muzzle velocity, hence energy.

Don't get hung up on "hyper velocity". What was fast yesterday isn't today. What is today won't be tomorrow. What matters is what kills.

Consider this: Target armor plays a role. You would use HE against a light armor of older APCs as a APFSDS round will fly right through and out the other side causing minimal damage.

These are some basic facts. They are not all-inclusive.

 

[snrdg082102]

Evening Vladika,

Thanks for posting and adding to the discussion. I agree with you about modern weapons systems, however in TNE the shattered Imperium is running the range of tech levels which means that somewhere one of the factions will be meeting up with rifled bores.

Old weapons can still take out targets given the right circumstances.

Thanks for the interesting tidbit about the Brits and all the other items.

Rifled gun barrels are practically never used in modern artillery and particularly direct fire guns. Fin stabilized munitions are FAR more accurate and can NOT be fired from a rifled barrel. (SOME exceptions CAN occur such as discarding sabot rounds)

HE and associated rounds do NOT penetrate anywhere near as well if spinning. It interferes with the formation of the gas jet.

In annual NATO tank firing competitions the British NEVER win. Reason: They are the only member nation using rifled tank barrels. (This may have changed, I've been out of the loop for awhile.) Note they don't use HE or HEAT rounds but a HESH (High Explosive Squash Head) round. It forms not a jet but spreads out and "spalls" off armor from the interior. US M728 Combat Engineer Vehicle uses the same type round and in a smooth bore. (It is not a tank, though it looks like one.)

Also, a mussel break can NOT be used with fin stabilized munitions. This is important for howitzers. In a true mortar, loaded from the tube end, a smooth bore is essential for the round to slide down the tube and hit the firing pin with enough force to fire.

In a long range gun, rifling WILL burn away very rapidly, forcing constant changes in many range calculations (hard without a computer and vast quantities of trial DATA) and frequent (Expensive) barrel replacement.

These "Rules" are nearly universal. You, and I, can find exceptions due to hardheadedness or very unusual circumstances of designs.

Traditionally, the longer the barrel, the greater the muzzle velocity. The greater the muzzle velocity, the greater the penetration of kinetic energy rounds. Energy=½ mv². From the equation it is easily seen the velocity is the controlling factor. Longer barrels are lighter than the vastly heavier breaches needed to achieve the same, or close, muzzle velocity, hence energy.

Don't get hung up on "hyper velocity". What was fast yesterday isn't today. What is today won't be tomorrow. What matters is what kills.

Consider this: Target armor plays a role. You would use HE against a light armor of older APCs as a APFSDS round will fly right through and out the other side causing minimal damage.

These are some basic facts. They are not all-inclusive.