Ballistics shells

Explosive D is approx 80% as brisant as TNT, as indicated by sand tests, but fragmentation tests in shell have shown it to be about 95% as brisant. Both expls have about the same rate of detonation at a d of 1.56g/cc hence, approx equality of brisance would be expected. The rate of detonation of Explosive D has been found to be somewhat affected, particularly at lower loading densities, by the granulation of the material, but this effect is not pronounced. Its expl strength is 98% that of TNT, as evidenced by the ballistic pendulum test (see below)... 

Having outlined the form and function of two typical star shells we can now attempt to quantify some of the ballistic effects that give rise to the performance of these spectacular fireworks. 

Muzzle Velocity of the Shell. A further equation based on gun ballistics has been proposed that allows an estimation to be made of the muzzle velocity of a shell [equation (4.6)],... 

The simplest external ballistics calculation is that in which a shell is hred vertically. This type of calculation has also been extended to include the case where a dud shell falls back to earth. 

BALLISTICS (INTERNAL) The science of internal ballistics is concerned with the propulsion of a projectile such as a shell along the tube of a mortar by gas pressure acting on the base of the shell, or, in the case of rockets, by the backward exhaust of the gas jet. 

BALLISTICS (EXTERNAL) Extemal ballistics deals with the science of the motion of bodies such as shells and rockets in the earth s atmosphere and under the effect of the earth s gravitational field. 

Target Practice (TP). This proj simulates the ballistic properties of service projs and is used for training in marksmanship. It may be made from completely inert-loaded service projs, or made from different metal parts and may contain a tracer and/or a spotting charge of BkPdr (Ref 52, p 1-33 1-34). Some TP projectiles used to be empty cast-iron shells (Ref 40b, p 4)... 

Expin Temp 300° Impact Sensitivity with 5kg wt 17cm maximum with no explns Friction Sensitivity with 60kg pressure — no explns and Power by Ballistic Mortar 64% of PA. It was used in Submarine Gun Incendiary Shells (Ref 5, p 362)... 

The 70/30 mixt had Expln Temp 237-46° Brisance by Sand Test 102% TNT Power by Ballistic Mortar 109% TNT Rifle Bullet Test 20% detonations and Impact Sensitivity by PicArsn Test 12.5 inches (TNT 14). It was reported to be toxic, not very stable, and reactive with metals in the presence of moisture. Used pressed by Army and Navy as an Auxiliary Booster in some Bombs and Shells (Ref 1, pp 31 32 and Ref 5, p 365)... 

Shoeiyaku. Pentaerythritol Tetranitrate (PETN), C(CH2ON02)4 mw 316.14, N 17.72% wh crysts, d 1.77, mp 141° Brisance by Plate Dent Test 129% TNT Explosion Temperature 225° (decomp in 5 secs) Impact Sensitivity BurMines-App, 2-kg Wt 17cm (vs 100+ for TNT) Power by Ballistic Mortar Test 145% TNT Rate of Detonation 8300m/sec (Ref 8, p 276). Pressed PETN was used in Army 7.7 12.7-mm Fuzeless Projectiles and 20-mm MG Projs. Also in Boosters. Its mixt with TNT is called Pentoriru (qv). PETN with 8.5% wax was used for loading 20-mm Shells. Its mixtures with RDX were used in 7.7 12.7-mm Projectiles. PETN was also used in Incendiary Mixtures (Ref 1, p 27 Ref 5, p 372)... 

Impact Sensitivity — comparable with PETN(FI) Power by Ballistic Mortar Test — 108% TNT Power by Trauzl Test — 115% TNT Thermal Stability at 135° — acidic in 30 mins Uses Due to the presence of excess O, HNEt forms in mixts with HE s deficient in O, very powerful e pls. Claessen (Ref 2) patented in 1913 several mixts with TNT suitable as bursting or booster chges of artillery shells. 

AP shell intended to penetrate face-hardened armor is usually provided with a slightly blunted nose which is fitted with a cone-shaped cap made of soft and tough forged alloy steel, face hardened. Such shell is called APC (armor-piercing capped). The cap of this shell is fitted with a conical cup, called windshield or ballistic cap, (also called false ogive) the purpose of which is... 

Wilson, Yaw of Repose on Spinning Shells , SC-RR-70-155, Sandia Labs, Albuquerque (1970) 6) Ibid, Effect of Yaw of Repose on Ballistic... 

B4 or Type 2 Explosives. Lt grey powdery mixts of TNAns 60 or 70 w ith A1 40 or 30% used in Japanese incendiary submarine gun shells. The props of the 60/40 mixt were dl.90 (cast), power by ballistic pendulum 64%(PA= 100%), brisance by copper cylinder crusher 82% (PA=100%), explosion point 300 to 505°, impact sensitivity with 5-kg wt I7cm(max for no expins) and friction sensitivity 60kg(max pressure between two rubbing surfaces)... 

As examples of ballistic tests for explosives may be cited brisance, power, velocity of detonation tests, etc. Some of these tests are briefly described under Physical Tests, Vol 1, p VUrf, of this Encyclopedia, others will be described later. Ballistic tests for shells, bofilbs, fOCkctS, grcliaucS, ClC limy iiiCiUuc flag mentation characteristics, penetration in armor... 

All of these improvements could not remove two props of BkPdr which render it not very desirable for use as a military propellant- low ballistic potential and production on firing of enormous amts of smoke, which quickly make the location of artillery obvious to the enemy. Its low power, brisance and velocity of detona-tion make it too weak for use as a bursting chge for any but cast-iron shell... 

The formation of one or more cavities(air spaces or voids) in cast-loaded solid, expl or proplnt c hges is called cavitation (See under Loading of Ammunition). A cavity in a HE chge of a shell may cause premature expln in the gun because of collapse of the chge under the force of acceleration. A cavity in a propint chge may affect its ballistic characteristics(Ref 1). Cavities in loaded ammo may be discovered by x-ray devices such as Betatron(qv)... 

Sheflite. Brit WWII expl, same as US 70/30 Tridite (qv), contg 70% PA and 30% 2,6-Dinitro-phenol (DNPh). It was used to cast load AP (armor piercing) bombs and shells. Its properties were yellow cream colored solid d 1.62g/cc mp 83° ballistic strength, 91% TNT brisance, 38.5g sand crushed vs 43.0g for TNT expl temp, 300-15° impact sensitivity, PicArsn app with 2kg wt, 14" vs 14" for TNT rifle bullet impact, 0 to 20% detonations from impact of. 30 cal bullet fired froma90 distance stability, compatibility of metals, sol and toxicity, same as PA (Ref 1)... 

The brisance of Tritonal is 100% of that of TNT, as judged by sand test values, but plate dent tests indicate it to be only 93% and fragmentation tests of shell charges show it to be but 91% as brisant as TNT. The rate of detonation of cast Tritonal is approx 97% that of cast TNT. The heat of expln of Tritonal is 60% greater than that of TNT, but Tritonal is only 124% as powerful, as measured by the ballistic pendulum test. When tested for blast effect, Tritonal has relative peak pressure and positive impulse values of 113 and 118%, respectively, of those for TNT... 

Ever since the introduction of the comparison microscope into the field of advanced firearms indentification in about 1925, people engaged in this work have been processing ballistics evidence, bullets and shells, in exactly the same manner. This can only be done by examining each piece of evidence separately and individually, one piece at a time, and comparing this evidence, again separately and individually, by the utilization of the comparison microscope. Today, we in the field of firearms identification still process evidence in exactly the same manner using the same techniques and basically the same instrument that was applied almost fifty years ago. 

Since the spherical shape is unfavorable from internal ballistical considerations (very degressive), follows, a thorough -+ Surface Treatment the purpose of which is to sheathe the faster-burning core by a slower-burning shell. 

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