Weight Vs Power.

[surffoils]

Much like the weight to power ratio of a car, if you lower the weight of the projectile it should increase the speed/ power of the delivery.
Has anyone done any investigations into how good a pneumatic can fire a projectile...I’m thinking of testing micro weight projectiles of less than a gram. They may not destroy much but they could get great velocity and penetration.
Any thoughts about design or things to consider ?

[farcticox1]

Reducing weight will increase speed for sure, I found that with 0.2g and 0.12g airsoft.
Chrono test @150 psi with 0.12g = 860fps = 4 joules
0.2g = 694fps = 4 joules


But it will effect the energy calculation as well

http://www.shooterscalculator.com/bulle ... energy.php

[hectmarr]

The calculator is very useful. I did not know him

[jackssmirkingrevenge]

Has anyone done any investigations into how good a pneumatic can fire a projectile...I’m thinking of testing micro weight projectiles of less than a gram. They may not destroy much but they could get great velocity and penetration

The thing about reducing the diameter of your projectile and therefore your barrel means that if you want high velocities, you have to significantly up the pressure if you want to see meaningful results. The alternative is to use a sabot that allows a very light projectile to be accelerated in a larger diameter barrels.

It's basically the two approaches that have been applied to high velocity anti-tank guns. Anthony Williams has a good article on the history of high velocity guns that's worth a read:

The Armour Problem

Since the first armoured fighting vehicles lumbered across the battlefield, the need to provide a weapon which could penetrate their armour has held a high priority in military equipment planning. There are two basic ways of achieving this; by explosives (particularly shaped charges) and via the kinetic energy of a solid projectile.

The use of explosives, which did not become important until part way through the Second World War, is the only effective technology suitable for guided missiles and light infantry weapons. However, kinetic energy weapons (otherwise known as tank guns) remain the most effective means of dealing with armour.

Until the Second World War, the armour problem was not too serious as only a few heavy tanks had any significant thickness of armour, most being protected only against the armour-piercing versions of the standard small arms cartridge. It was therefore feasible for a kinetic energy weapon to be light enough for a single infantryman to use; and the anti-tank rifle was duly born.

The granddaddy of them all was the German l3x92mm Tank und Flieger round, which emerged in 1918 in a massive Mauser bolt-action rifle. Velocity was not significantly greater than the standard military rifle, the armour penetration being achieved by bullet weight. Britain followed a similar route in developing the .55" Boys rifle in the 1930s, but by then the German and Polish engineers were following a different path. They had discovered that velocity was extremely important in achieving effective penetration and accordingly designed rifles around cartridges which kept their standard military calibres of 7.92mm but achieved very high velocities through the use of massive cartridge cases.

Thus were born the 7.92x107mm Maroszek and 7.92x94mm Panzerbuchse rounds. They both were loaded with heavy bullets for the calibre, weighing 198 and 225 grains respectively. The Maroszek is reported to have achieved nearly 4,200 fps; the Panzerbusche has been claimed to achieve around 4,000 fps although American tests showed only 3,540 fps. Nonetheless, this was sufficient to penetrate 1.25" of armour at 100 yards. Needless to say, barrel wear was fierce, with a maximum of around 200 rounds being possible before performance reduced significantly.

While anti-tank rifles soon became obsolete as armour thickness increased, they have recently experienced something of a revival in attempts to deal with lesser-armoured vehicles, often with the dual role of long-range sniping rifles. The smallest example of these is the Conjay Firearms sniper rifle, chambered for the .300 Holland & Holland cartridge (while not the largest .30 Magnum, the tapering case facilitates extraction with high pressure loadings). In its anti-armour role, it fires a 125 grain FFV tungsten-cored bullet at around 4,000 fps, sufficient to penetrate 45mm of stainless steel at 100 metres, although the performance of the light bullet drops off sharply with range.

Returning to World War 2, efforts in defeating tanks shifted to tank guns and anti-tank artillery. The use of "magnum" cartridges to achieve the required high velocity was particularly noticeable in anti-tank guns, tank guns sometimes employing a larger calibre at a lower velocity in order to utilise a more effective explosive shell. Perhaps the best-known of the magnum rounds was the German 8.8cm L71, originally designed as an antiaircraft weapon but also used in the "King Tiger" tank, as well as various anti-tank equipment, which achieved 3,340 fps and was the outstanding armour penetrator of the Second World War.

In the technical hothouse of the last World War, several different methods of achieving improved armour penetration without incurring the size and weight penalties of the big magnums were sought. The simplest was to design a type of shot which contained a sub-calibre tungsten core surrounded by a fixed light alloy sleeve to fit the bore of existing antitank guns. The whole shot weighed much less than usual, permitting a much higher muzzle velocity. When the shot hit the target, the light-alloy sleeve broke up, leaving the tungsten core to penetrate.

This type of shot, known as APCR (Armour Piercing, Composite, Rigid) in British service and HVAP (High Velocity Armour Piercing) to the Americans, was also used by the Germans (who called it PzGr 40 or Arrowhead shot) although to a lesser extent because of their shortage of tungsten. The performance leap could be huge: the 5cm Pak 38 showed an increase in velocity from 2,700 to 3,900 fps with maximum penetration at 250 metres increased from 88 to 141mm. The disadvantage was that the light and wide projectile lost velocity and penetration very quickly and was therefore only useful at short range.

The problem was to achieve and sustain a high velocity over battle ranges, which required a large calibre at the chamber end of the gun, for maximum interior ballistic efficiency, but a small-calibre projectile for optimum exterior ballistics and penetrative power. The first attempt to achieve this was a developmental blind alley; the cone, taper or squeeze-bore gun.

This was first developed to prototype stage by Gerlich in the 1920s, who demonstrated examples at Woolwich in 1932. A cartridge case, apparently based on an extended .303" (7.7mm) necked out to 9.25mm, fired a 95 grain projectile with an emergent calibre of 7mm at a muzzle velocity of 4,880 fps. The British showed interest and continued to experiment for some years, but the only service weapon using this principle was the 2-pdr Littlejohn (a translation of the name of the Czech inventor, Janecek).

The Germans were the first to introduce taper-bore weapons. They required entirely new gun barrels, with a calibre which reduced from the chamber to the muzzle, and a tungsten shot of muzzle calibre, fitted with flanges of chamber calibre. As the shot proceeded down the barrel, the flanges were squeezed into the shot, leading to the nickname "squeeze bore". Anti-tank guns of 2.8/2.0, 4.2/2.9 and 7.5/5.5cm bore were introduced. The velocity champion was the 2.8cm PzB 41, with a 28mm cartridge reducing to 20mm at the muzzle, which achieved a muzzle velocity of just under 4,600 fps. These weapons were highly effective, but doomed in German service because of the tungsten shortage (steel shot would disintegrate on impact at these velocities).

The British adopted the same principle with the Littlejohn adaptor, which consisted of a squeeze-bore extension added to an otherwise conventional 2-pdr armoured car gun. Again, it led to a great increase in performance with the around 4,200 fps muzzle velocity, but was unpopular because of the necessity to remove the adaptor before full-calibre HE shells could be fired. In the event, the special shot was sometimes fired without the adaptor (effectively becoming APCR) which worked quite well at short range. Examples exist of a Littlejohn HE shell experimentally produced for the 2-pdr, but this was too small to be worthwhile.

The ultimate answer was the APDS shot, or Armour Piercing Discarding Sabot. This was similar to the APCR, except that the light-alloy sleeve was designed to break up and fall away from the shot as soon as it left the muzzle, so the velocity was sustained over a much longer range. The technical problems were considerable (and accuracy was never as good as with conventional shot) but, once solved, APDS became the standard tank AP ammunition until the development of the fin-stabilised round. The muzzle velocity of the 6-pdr tank/anti-tank gun rose from under 3,000 to over 4,000 fps with APDS; the succeeding 17 pdr APDS also hit nearly 4,000 fps, enough to penetrate even the 68-ton King Tiger tanks at 1,000 yards. The British 105mm L7 gun, optimised for APDS, became NATO's main tank gun through the 1960s and 70s, with a muzzle velocity of 4,800 fps.

The same principle has been adopted to allow smaller weapons to deal with more lightly-armoured vehicles. The 30mm Rarden gun, standard fitting to British reconnaissance and armoured infantry fighting vehicles, fires an APDS projectile at 3,850 fps. In still smaller calibres, the US Army’s SLAP (Saboted Light Armour Penetrator) programme led to an APDS round for the .50 Browning (440 grain, 7.62mm projectile at 4,000 fps).

More recently, the application of APDS technology to anti-aircraft guns has become a reality. First explored by the Germans towards the end of WW2 (essentially to launch small HE projectiles from the 88mm gun) this is now re-emerging in much smaller calibres of 25-35mm, in the form of FAPDS (Frangible APDS). The projectile is the same shape as an APDS shot but is designed to break up into a hail of fragments as soon as it penetrates the target. The major advantage for AA purposes is the much shorter time of flight of the high-velocity projectile, which greatly increases the effective range of the gun.

The current state of the art is represented by the APFSDS, or Armour Piercing Fin Stabilised Discarding Sabot shot. This developed because it became apparent that a long thin shot loses less velocity and achieves better penetration than a conventional APDS shot. However, there is a limit to the length of shot which can be stabilised by rifling-induced spinning. It was therefore necessary to introduce tailfins to keep such long projectiles flying towards the target. As the rifling was not required (in fact, it destabilises the long projectiles), smoothbore barrels were developed which also permitted a higher velocity due to less drag. The British have resisted this development because of the resulting loss of accuracy when firing HESH shells, so have retained rifled barrels. Instead, slip rings on the sabot are utilised to minimise the spin rate imparted to the FS projectile. However, 120-125mm smoothbore tank guns have now become standard, achieving muzzle velocities of up to 5,500 fps.

This technology is not just applied to tank guns. One of the new breed of portable anti-armour weapons, the Steyr 15.2mm IWS 2000 anti-materiel rifle, fires a 5.5mm fin-stabilised projectile weighing 300 grains at over 4,750 fps, capable of penetrating 40mm of armour steel at 1,000 metres.

In the world of spudguns, you're probably better off with a high-mix hybrid as opposed to a pneumatic for some serious velocities and penetration.

The calculator is very useful. I did not know him

My go-to calculator online for muzzle energy is this one.

[hectmarr]

Has anyone done any investigations into how good a pneumatic can fire a projectile...I’m thinking of testing micro weight projectiles of less than a gram. They may not destroy much but they could get great velocity and penetration

The thing about reducing the diameter of your projectile and therefore your barrel means that if you want high velocities, you have to significantly up the pressure if you want to see meaningful results. The alternative is to use a sabot that allows a very light projectile to be accelerated in a larger diameter barrels.

It's basically the two approaches that have been applied to high velocity anti-tank guns. Anthony Williams has a good article on the history of high velocity guns that's worth a read:

The Armour Problem

Since the first armoured fighting vehicles lumbered across the battlefield, the need to provide a weapon which could penetrate their armour has held a high priority in military equipment planning. There are two basic ways of achieving this; by explosives (particularly shaped charges) and via the kinetic energy of a solid projectile.

The use of explosives, which did not become important until part way through the Second World War, is the only effective technology suitable for guided missiles and light infantry weapons. However, kinetic energy weapons (otherwise known as tank guns) remain the most effective means of dealing with armour.

Until the Second World War, the armour problem was not too serious as only a few heavy tanks had any significant thickness of armour, most being protected only against the armour-piercing versions of the standard small arms cartridge. It was therefore feasible for a kinetic energy weapon to be light enough for a single infantryman to use; and the anti-tank rifle was duly born.

The granddaddy of them all was the German l3x92mm Tank und Flieger round, which emerged in 1918 in a massive Mauser bolt-action rifle. Velocity was not significantly greater than the standard military rifle, the armour penetration being achieved by bullet weight. Britain followed a similar route in developing the .55" Boys rifle in the 1930s, but by then the German and Polish engineers were following a different path. They had discovered that velocity was extremely important in achieving effective penetration and accordingly designed rifles around cartridges which kept their standard military calibres of 7.92mm but achieved very high velocities through the use of massive cartridge cases.

Thus were born the 7.92x107mm Maroszek and 7.92x94mm Panzerbuchse rounds. They both were loaded with heavy bullets for the calibre, weighing 198 and 225 grains respectively. The Maroszek is reported to have achieved nearly 4,200 fps; the Panzerbusche has been claimed to achieve around 4,000 fps although American tests showed only 3,540 fps. Nonetheless, this was sufficient to penetrate 1.25" of armour at 100 yards. Needless to say, barrel wear was fierce, with a maximum of around 200 rounds being possible before performance reduced significantly.

While anti-tank rifles soon became obsolete as armour thickness increased, they have recently experienced something of a revival in attempts to deal with lesser-armoured vehicles, often with the dual role of long-range sniping rifles. The smallest example of these is the Conjay Firearms sniper rifle, chambered for the .300 Holland & Holland cartridge (while not the largest .30 Magnum, the tapering case facilitates extraction with high pressure loadings). In its anti-armour role, it fires a 125 grain FFV tungsten-cored bullet at around 4,000 fps, sufficient to penetrate 45mm of stainless steel at 100 metres, although the performance of the light bullet drops off sharply with range.

Returning to World War 2, efforts in defeating tanks shifted to tank guns and anti-tank artillery. The use of "magnum" cartridges to achieve the required high velocity was particularly noticeable in anti-tank guns, tank guns sometimes employing a larger calibre at a lower velocity in order to utilise a more effective explosive shell. Perhaps the best-known of the magnum rounds was the German 8.8cm L71, originally designed as an antiaircraft weapon but also used in the "King Tiger" tank, as well as various anti-tank equipment, which achieved 3,340 fps and was the outstanding armour penetrator of the Second World War.

In the technical hothouse of the last World War, several different methods of achieving improved armour penetration without incurring the size and weight penalties of the big magnums were sought. The simplest was to design a type of shot which contained a sub-calibre tungsten core surrounded by a fixed light alloy sleeve to fit the bore of existing antitank guns. The whole shot weighed much less than usual, permitting a much higher muzzle velocity. When the shot hit the target, the light-alloy sleeve broke up, leaving the tungsten core to penetrate.

This type of shot, known as APCR (Armour Piercing, Composite, Rigid) in British service and HVAP (High Velocity Armour Piercing) to the Americans, was also used by the Germans (who called it PzGr 40 or Arrowhead shot) although to a lesser extent because of their shortage of tungsten. The performance leap could be huge: the 5cm Pak 38 showed an increase in velocity from 2,700 to 3,900 fps with maximum penetration at 250 metres increased from 88 to 141mm. The disadvantage was that the light and wide projectile lost velocity and penetration very quickly and was therefore only useful at short range.

The problem was to achieve and sustain a high velocity over battle ranges, which required a large calibre at the chamber end of the gun, for maximum interior ballistic efficiency, but a small-calibre projectile for optimum exterior ballistics and penetrative power. The first attempt to achieve this was a developmental blind alley; the cone, taper or squeeze-bore gun.

This was first developed to prototype stage by Gerlich in the 1920s, who demonstrated examples at Woolwich in 1932. A cartridge case, apparently based on an extended .303" (7.7mm) necked out to 9.25mm, fired a 95 grain projectile with an emergent calibre of 7mm at a muzzle velocity of 4,880 fps. The British showed interest and continued to experiment for some years, but the only service weapon using this principle was the 2-pdr Littlejohn (a translation of the name of the Czech inventor, Janecek).

The Germans were the first to introduce taper-bore weapons. They required entirely new gun barrels, with a calibre which reduced from the chamber to the muzzle, and a tungsten shot of muzzle calibre, fitted with flanges of chamber calibre. As the shot proceeded down the barrel, the flanges were squeezed into the shot, leading to the nickname "squeeze bore". Anti-tank guns of 2.8/2.0, 4.2/2.9 and 7.5/5.5cm bore were introduced. The velocity champion was the 2.8cm PzB 41, with a 28mm cartridge reducing to 20mm at the muzzle, which achieved a muzzle velocity of just under 4,600 fps. These weapons were highly effective, but doomed in German service because of the tungsten shortage (steel shot would disintegrate on impact at these velocities).

The British adopted the same principle with the Littlejohn adaptor, which consisted of a squeeze-bore extension added to an otherwise conventional 2-pdr armoured car gun. Again, it led to a great increase in performance with the around 4,200 fps muzzle velocity, but was unpopular because of the necessity to remove the adaptor before full-calibre HE shells could be fired. In the event, the special shot was sometimes fired without the adaptor (effectively becoming APCR) which worked quite well at short range. Examples exist of a Littlejohn HE shell experimentally produced for the 2-pdr, but this was too small to be worthwhile.

The ultimate answer was the APDS shot, or Armour Piercing Discarding Sabot. This was similar to the APCR, except that the light-alloy sleeve was designed to break up and fall away from the shot as soon as it left the muzzle, so the velocity was sustained over a much longer range. The technical problems were considerable (and accuracy was never as good as with conventional shot) but, once solved, APDS became the standard tank AP ammunition until the development of the fin-stabilised round. The muzzle velocity of the 6-pdr tank/anti-tank gun rose from under 3,000 to over 4,000 fps with APDS; the succeeding 17 pdr APDS also hit nearly 4,000 fps, enough to penetrate even the 68-ton King Tiger tanks at 1,000 yards. The British 105mm L7 gun, optimised for APDS, became NATO's main tank gun through the 1960s and 70s, with a muzzle velocity of 4,800 fps.

The same principle has been adopted to allow smaller weapons to deal with more lightly-armoured vehicles. The 30mm Rarden gun, standard fitting to British reconnaissance and armoured infantry fighting vehicles, fires an APDS projectile at 3,850 fps. In still smaller calibres, the US Army’s SLAP (Saboted Light Armour Penetrator) programme led to an APDS round for the .50 Browning (440 grain, 7.62mm projectile at 4,000 fps).

More recently, the application of APDS technology to anti-aircraft guns has become a reality. First explored by the Germans towards the end of WW2 (essentially to launch small HE projectiles from the 88mm gun) this is now re-emerging in much smaller calibres of 25-35mm, in the form of FAPDS (Frangible APDS). The projectile is the same shape as an APDS shot but is designed to break up into a hail of fragments as soon as it penetrates the target. The major advantage for AA purposes is the much shorter time of flight of the high-velocity projectile, which greatly increases the effective range of the gun.

The current state of the art is represented by the APFSDS, or Armour Piercing Fin Stabilised Discarding Sabot shot. This developed because it became apparent that a long thin shot loses less velocity and achieves better penetration than a conventional APDS shot. However, there is a limit to the length of shot which can be stabilised by rifling-induced spinning. It was therefore necessary to introduce tailfins to keep such long projectiles flying towards the target. As the rifling was not required (in fact, it destabilises the long projectiles), smoothbore barrels were developed which also permitted a higher velocity due to less drag. The British have resisted this development because of the resulting loss of accuracy when firing HESH shells, so have retained rifled barrels. Instead, slip rings on the sabot are utilised to minimise the spin rate imparted to the FS projectile. However, 120-125mm smoothbore tank guns have now become standard, achieving muzzle velocities of up to 5,500 fps.

This technology is not just applied to tank guns. One of the new breed of portable anti-armour weapons, the Steyr 15.2mm IWS 2000 anti-materiel rifle, fires a 5.5mm fin-stabilised projectile weighing 300 grains at over 4,750 fps, capable of penetrating 40mm of armour steel at 1,000 metres.

In the world of spudguns, you're probably better off with a high-mix hybrid as opposed to a pneumatic for some serious velocities and penetration.

The calculator is very useful. I did not know him

My go-to calculator online for muzzle energy is this one.

Excellent reading! It has no waste. I have learned something more.
Very good your calculator

[D_Hall]

It's basically the two approaches that have been applied to high velocity anti-tank guns. Anthony Williams has a good article on the history of high velocity guns that's worth a read:

Interesting reading and my takeaway is "it all depends." I say this because for a period in my career I was paid to develop armor. What we found during our admittedly niche studies of a problem that I'm not going to discuss, was that penetration scaled more with momentum than it did with energy for a given diameter. That is to say, better to shoot a slow rod than a fast BB even at the same muzzle energies.

[jackssmirkingrevenge]

That is to say, better to shoot a slow rod than a fast BB even at the same muzzle energies.

Anyone familiar with archery would immediately agree, the levels of penetration achieved by relatively heavy and slow arrows compared to bullets is quite remarkable. We also established on this forum that putting a needle through a coin was not an exceptionally difficult task.

The Röchling shell also springs to mind, a low velocity projectile compared to a standard shell yet with fantastic penetration against contemporary fortifications by virtue of its high sectional density:

[Firstshotwins]

Generally speaking, losing the weight would increase speed + distance but there is also that sweet spot. Where a projectile can be heavy / cover that perfect amount of distance before losing impact power. You can only find that through testing. However, once you do . . . oh boy

[Erinrookes]

Weight to control is one approach to get a general thought of speeding up execution. For instance, in the event that I have a 3500 lb vehicle with 215 strength, I just partition 3500 by 215 to get a weight to control proportion of 16.28 lbs per pull. A similar vehicle with 250 hp would have a weight to control proportion of 14 lbs for every torque.

[Ellyanderson]

I thinktThe converse of capacity to-weight, weight-to-control proportion (control stacking) is an estimation ordinarily connected to air ship, autos, and vehicles all in all, to empower the correlation of one vehicle's execution to another11