Ammonium Paratungstate Process

APT is produced by separating tungsten from its ore. Once the ammonium paratungstate is prepared, it is heated to its decomposition temperature, 600 °C. Left over is WO₃, tungsten oxide. At that point, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to powder, leaving behind water vapor. From there, the tungsten metal powder can be fused into any number of things, from wire to bars to other shapes.

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Tungsten Related Oxide could drived from APT

Intermediates, such as tungsten trioxide, tungsten blue oxide, tungstic acid, and ammonium metatungstate can be derived from APT as shown beyong, either by partial or complete thermal decomposition or by chemical attack.

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Adjusting the balance of bullets - 02

By placing a plastic ball into the jacket, compressing it, and then placing a small quantity of

tungsten powder in the jacket followed by a final plastic ball, the weight can be increased and the

balance shifted, so that a combination of material quantities and positions can be developed that will

deliver good stability with any of the weights. Moving the weight toward the tip tends to make the

bullet more stable, but a point will be reached where the bullet does not turn to follow the trajectory

arc. At that point, the bullet is “over-stable” in the sense that rifling no long is required to keep it

pointed nose first, but instead the mass forward of the center of form will do this. If the trajectory is

very flat, or the range is quite short, the bullet will appear to be accurate.

But if the trajectory or range is normal for a rifle or long-range handgun, the bullet will be

pointed in the same direction as it was when it emerged from the barrel all the way to the target. That

is, it refuses to turn because it is so stable. In this case, the bullet presents an angle to the direction of

flight and thus offers a very low ballistic coefficient, compared to the same bullet with the center of

gravity shifted slightly further toward the rear. Extreme examples have resulted in the bullet dropping

sideways through the target (and the normal wind and air currents cause it to drift in an extreme

pattern from shot to shot, which appears to make the bullet seem inaccurate—and in practical terms,

it is).

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Adjusting the balance of bullets - 01

The center of form of a bullet is generally defined as the point at which all of the axial forces could mathematically be concentrated from their actual vectors. The center of gravity of the bullet is the point where the bullet could be balanced against gravity. Although the actual center of gravity and center of form are located inside the bullet, we can simulate the location of the center of gravity by attempting to balance the bullet on a razor blade. The point along the side of the bullet where it most nearly will balance is close, in practical terms, to the actual center of gravity.

The center of form is harder to ascertain by external testing, because it is a measure of the forces working upon the bullet as it flies through the air. However, we can shift the center of gravity within the airframe of a given bullet by using a combination of two different densities of material in the core, each in its own separate “compartment”, so that the ratio of length of each will determine where the center of gravity lies.

For instance, linear polyethylene balls are available in various diameters that will slip easily into nearly any caliber of bullet jacket. These polymer balls will compress under swaging pressure to fill the space available, yet add only a few grains to the total bullet weight. Filling the entire bullet with two or more plastic balls creates a standard length of bullet that has only a few more grains than the jacket itself. A typical example would be a 58 grain .308 rifle bullet, which is normal length for a 168 grain bullet. Another would be a 40 grain 9mm which has the appearance of a normal 140 grain bullet.

These light bullets can be fired at extremely fast speeds with the correct charge of fast burning powder, but they generally are not accurate.

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Short lengths with normal weight bullets

Using a dense material also means that the length of a normal weight bullet can be shortened, for such purposes as gaining additional powder capacity in the case, fitting into a short throated barrel without impacting against the rifling, or allowing the innovative use of longer wildcat cases (such as arimmed .30 rifle case cut back to make an extra long .44 handgun case, which could fit a .44 Magnum revolver cylinder). In some situations where the limit of bullet length is all that prevents an innovative idea from working, using a normal weight with a tungsten core can reduce bullet length, and thus reduce the overall cartridge length enough to try a new concept.

The amount of reduction in length is approximately 60 percent of the original lead core bullet length, when filled with tungsten powder. This will vary with the ratio of jacket to core weight, of course, but it is normally safe to assume that a minimum of 25% shorter length will result in the same weight of bullet, when changing from a lead core to a tungsten core. A simple example is the use of a slower burning, bulkier powder behind a normal weight .380 or .25 ACP bullet when used in a pisto that has been equipped with a longer than usual barrel. The shorter bullet allows more powder room in the cartridge, which can then be used to develop safe loads that deliver a longer burn curve to accelerate the bullet through a longer barrel than would normally be used in that caliber.

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Heavy weights in standard length bullets

The most obvious use of tungsten powder in bullet design is to make heavy bullets that will fit into normal length chambers, feed through standard length actions and fit into normal magazines and revolver cylinders.

Because the bullet density is increased, and its length remains the same, the spin rate required to stabilize it does not change appreciably. This means a second benefit is that the normal twist rate of barrel should stabilize the heavy tungsten core bullet, whereas it would not stabilize a lead core bullet of the same weight (since the spin rate required increases with bullet length, and only incidently with the bullet weight because normally the density of material is not changed).

In addition to the savings in not having to purchase special barrels to fire these heavy bullets accurately, the normal length tungsten core bullets have the additional benefit of not wasting additional energy in spinning faster, and because they do not have to spin faster, they also have less problem with radial imbalances than a conventional heavy weight lead core bullet. It is well known that the faster a bullet is spun about its axis, the more centrifugal force is generated by slight imbalances in the jacket wall thickness, tiny voids or other anomolies of construction. If all else were equal,the bullet which can be stablilized with the lowest twist rate will tend to be more accurate, and this would be the tungsten core bullet. Typical uses might be 80-100 grain .224 bullets, 130-145 grain .243 bullets, and 200-250 grain .308 bullets for long range, high delivered energy hunting loads or stable target rounds, or extra-heavy handgun bullets that will not protrude either into the case or project beyond the standard cartridge length

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Use of Tungsten in Bullet Design - 01

Tungsten as a solid material is difficult and expensive to machine because of its extreme hardness, but as a powder, it can be compacted into a bullet jacket at normal swaging pressures used for lead core bullets. With the proper grade and quality of particle size control, tungsten powder is relatively easy to handle and compacts to nearly the same density as solid metal.

Tungsten is approximately 1.7 times heavier than lead. A tungsten core bullet having the same length, caliber and shape as another bullet with a lead core would weigh more. The exact amount could be calculated by first weighing the bullet jacket, then subtracting this from the total bullet weight, and multiplying the resultant lead core weight by 1.7, and finally adding back the jacket weight. For instance, a 168 grain .30 caliber match bullet with a lead core typically would have a 50 grain jacket and a 118 grain lead core. An identical appearing tungsten core bullet would weigh 250.6 grains

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