Headstamp Markings on Ammunition Introduction

Union Metallic Headstamp

A cartridge headstamp is a mark, or series of marks impressed, or sometimes embossed, on the head of the cartridge case during its manufacture. The mark can consist of numbers, letters, trademarks, figures or any combination of these. Systems of headstamp markings are used worldwide. They can be in any language, numbering system or can relate to any calendar. From these impressions, one can, depending on the type of ammunition and its origin, determine the manufacturer, calibre, type, date of...

Priming Compounds and Primers Introduction

A priming compound is a highly sensitive explosive chemical which, when struck by the firing pin or hammer of a weapon, will explode with great violence, causing a flame to ignite the propellant. This explosive chemical is often mixed with other chemicals which provide oxygen to assist in the production of the flame, a fuel to increase the length and temperature of the flame and ground glass as an abrasive to assist in the initial ignition of the explosive. In the realms of forensic science,...

Bullet performance and wounding capabilities

This is another of those subjects surrounded by myth and misinformation. In many ways, this is understandable as the number of factors influencing how a bullet reacts on entering a human body is so diverse as to make a scientific study of the subject virtually impossible. If the body were made uniformly from a material of constant density, it would be extremely simple to simulate the effects of a bullet. The body is, however, full of voids with a hard bone skeleton and is associated...

Ricochet Analysis Introduction

Projectile Ricochet

When a bullet strikes any surface, there is a critical angle at which the bullet will bounce off or ricochet from the surface rather than penetrate. After ricocheting from the surface, the missile will lose a considerable amount of its velocity anything up to 35 in test firings and, invariably, lose its stability. This is contrary to the popular belief that a ricocheting bullet will carry further than one fired at the elevation for maximum range. The actual degree at which a bullet will...

Recovery methods for fired bullets

If a weapon has been recovered, it will be necessary to compare fired ammunition from this weapon with fired ammunition recovered from the scene. Obtaining a series of test cartridge cases from a self-loading pistol presents little difficulty as they merely have to be picked up. Obtaining fired bullets in a near pristine condition is, however, a little more difficult. In the past, cotton waste or wadding has been used, but this material can be quite abrasive to soft-lead bullets especially...

Penetration potential

The penetration of various materials can be of great assistance in the investigation of shooting incidents. It is also of considerable general interest if for no other reason than to show how often the movie makers and novel writers make appalling blunders. In the past, one of the standard tests performed to assess bullet and cartridge performance was the penetration of pine boards of various thicknesses. This, as with any other type of penetration test, is plagued with inaccuracies. Many...

Methods of measuring barrel pressure

Homemade Guns And Homemade Ammo

Assuming that the weapon is in good condition and that the correct type of ammunition is being used, it is the pressure produced in the barrel which ultimately decides whether the bullet will either reach the muzzle, exit from the barrel at an acceptable velocity or destroy the weapon completely. Often weapons are received with reloaded or home- made ammunition and for safety sake, it is often necessary to determine whether the ammunition is in fact safe to fire. At other times, it is necessary...

Cartridge nomenclature

A basic understanding of this subject is essential as it is an area where the inexperienced can really show lack of knowledge. Knowing the difference between a 9 x 18 and 9 x 19 mm cartridge, for example, may seem a little insignificant, but it is an area where the unwary can easily be tripped up and made to look very foolish. Having said that, it is a vastly complicated subject, and there are very few set rules. The first identifier is whether the cartridge in question is referred to in metric...

Internal External and Terminal Ballistics

There are basically three types of ballistics, internal, external and terminal. Internal ballistics is the study of what happens within the barrel of a weapon from the moment the firing pin hits the primer to the time the bullets exits from the barrel. It is mainly concerned with propellant pressures, acceleration of the missile whilst it is in the bore, muzzle velocity and recoil. Esoteric considerations such as primer ignition time, primer pressure time curves and temperature also come within...

Identification of Calibre from the Bullet Entry Hole Introduction

Bullet Identification Markings

In skin and fabrics, it is, unless a wadcutter-type bullet is used, all but impossible to determine the calibre of a missile from its entry or exit hole. Wadcutter bullets, as discussed earlier, are intended for target practice. As such, they are designed to cut a clean hole through the target to facilitate the determination of the shooter' s accuracy. When round-nosed or even hollow-point bullets are used, the hole produced by the bullet is very much smaller than its calibre. In skin, this is...

Chemical tests for range of firing estimations

In cases where a SEM is not available, the tests described below can still be used. Great caution should be used with the interpretation of any results obtained from these tests as none of them is specific. At best, the results could be presumptive and at worst, only indicative. Sodium rhodizonate test. The most valuable of the available spot tests is the sodium rhodizonate test for lead. This test is a rapid and very cheap method for determining, in those cases where a microscopic examination...

Nontoxic and frangible bullets

Lead contamination of firing ranges, both indoor and outdoor, has been a continuing and serious problem. The US National Bureau of Standards claims that 80 of airborne lead on firing ranges comes from the projectile, whilst the remaining 20 comes from the combustion of the lead styphnate primer mixture. In the early 1980s, a concerted move was made towards eliminating this health hazard, especially at training facilities and indoor ranges. The first step in this process was to eliminate the...

General wound ballistic concepts

Carbine Exit Wound

There are three concepts generally held by most as to the effect of a bullet striking a human being. The first is that the bullet 'drills' its way through leaving a small entry and an equally small exit hole. The second is that the bullet leaves a small entry hole and an enormous exit hole. The third is that when someone is shot by anything other than an air rifle, the impact is enough to lift the person off his feet and send him flying through the air. Basically, all three concepts are...

Degree of shot dispersion

Benelli Raffaell Crio Choke Ret

The degree of dispersion of the shot is dependent on many factors, the most important of which are Cartridge type. The higher the pressure generated by the cartridge, the more the shot will be disrupted as it emerges from the barrel by the following gases. Whilst this effect is largely offset by the wads used in modern cartridges, it is a factor which does affect the dispersion of the shot. Wad type. The wadding in traditional shotgun cartridges consisted of an over-powder wad, a series of...

Angle of elevation of the barrel

With small arms bullets, it is found that the maximum range is attained at an elevation of about 29 From 29 to 35 there is little increase in range. The angle of elevation at which maximum range is obtained is called the critical angle. At elevations in excess of 35 , the maximum range attained begins to decrease. This is clearly illustrated in the following study which utilized a Swiss boat tailed bullet of 0.30 calibre, weighing 174 gr with a ballistic coefficient of 0.284 and a muzzle...

What is the maximum altitude that a bullet will attain

308 Bullet Flight Characteristic

As with many other subjects that one comes across in forensic firearms examinations, this has little real relevance in everyday case examinations. There was an occasion, however, when a commercial airliner which had been flying in the air space above Northern Ireland was found, on landing, to have a 7.62 mm calibre hole in one side of the tailfin. Unfortunately, the airline concerned was unwilling to have the tailfin dismantled and taken apart due to the costs involved, and it was not possible...

Brief History of Forensic Firearms Identification Introduction

As with any evolving science, the exact origins of forensic firearms identification are shrouded in obscurity. Exactly when it was first noted that fired bullets from a given weapon possessed a certain number of equally spaced impressed grooves, all inclined in the same direction and at the same angle, and which were the same on every other bullet fired through that weapon, will probably never be known. Likewise, it will never be known when the next logical step was taken to compare the width,...

Methods Used for Removal of Serial Numbers

It is often the case that stolen weapons will have the serial number obliterated in an attempt to hide the weapon 's origin. Methods of obliteration generally fall into the following categories This is simply removing the number by hand filing or grinding with a high-speed carborundum grinding wheel. This is often followed by polishing and then over-stamping with a new number. Handbook of Firearms and Ballistics Second Edition Brian J. Heard 2008 John Wiley amp Sons, Ltd. This merely involves...

Brief History of Ammunition Introduction

Detenation Rim Fire

The first forms of ammunition consisted of loose powder, carried in a flask or horn, and various projectiles which were loaded into the barrel from the muzzle end. These early projectiles were often irregularly shaped stone balls or arrowlike objects. By the fifteenth century, ammunition had become fairly standardized and consisted of 'black powder' propellant a mixture of charcoal, sulfur and potassium nitrate , followed by some wadding, a spherical lead ball and further wadding to retain it...