ABSTRACT

EVALUATION OF BULLET HOLES IN THE ABSENCE OF


BULLETS AND SMOOTHBORE FIREARMS

J K Sinha

Proceedings IAFS (1999) No.118 pp 87-88, LA,USA

Possible misleading conclusion. Caution necessary
while evaluating bullet holes.

In the absence of questioned bullet and suspect firearm, an examination of a bullet hole is usually helpful in evaluating problems of forensic significance. The shape of the hole indicates direction of fire. A circular hole signifies a right angle fire to the surface and an oval hole an angular fire. The dimension of the hole coupled with the wounding caused by the bullet indicates probable bullet caliber and type of firearm . An explosive wound indicates the firing of a high velocity projectile. These criteria hold well for a standard factory made rifled firearm using appropriate ammunition. But if the involved firearm is an illegal, non- standard firearm , then the aforesaid criteria do not hold well and any conclusion drawn may be misleading if all possibilities are not taken into account. Use of improvised non- standard illegal firearms is very common in crimes in developing countries where law for the possession of firearms is very stringent. In India, home made firearms designed to fire regular pistol, revolver and rifle ammunition are commonly used in criminal cases. They are typically smooth bored and are short barreled. They are usually manufactured very crudely having no definite and proper specifications. Their barrel lengths, chamber shapes and sizes and bore diameters vary widely. Thus, cartridges of same caliber, make and lot fired from such firearms show wide variations in their ballistics, not only from one firearm to the other but also from firing to firing. Consequently their wounding effects and hole dimensions also vary considerably.

An exhaustive study of bullet hole caused by smooth bore home made firearms, designed to fire pistol, revolver and rifle ammunition, has been made. It has been observed that unlike regular rifled firearms , the holes generally are either oval or key shape irrespective of their relative bullet-bore diameter. Whereas a circular hole, ordinarily, indicates a right angle fire, an oval hole may not in these instances necessarily signify an angular fire. The caliber and dimension of bullet, in the majority of cases , can be determined from a clearly demarcated "key hole". A general assessment can also be made , in some cases, about the type of firearm by incorporating casualty criteria and density of powder particles around the bullet hole. A clearly demarcated key hole, surrounded by unusually widely distributed powder particles, leads to an inference that the firearm involved is an over bore size firearm, if the wounding caused is apparently and significantly far less to that expected from a similar bullet fired from corresponding appropriate rifled firearm. An unusual phenomenon of a bent bullet forming curved key hole, from slightly over size bore firearms having misaligned chamber, has been observed. Experimental observations coupled with plausible theoretical reasons for evaluation of caliber, type of firearm and direction of fire from bullet hole, in the absence of firearm and bullet, will be discussed in the present paper.

Bent bullet

Bent bullet


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Wounding effect of bullets fired from smooth bore
homemade/improvised firearms and modified ballistic table


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