Minimum velocity necessary for nonconventional projectiles to penetrate the eye: an experimental study using pig eyes

To satisfy the Criminal Code of Canada's definition of a firearm, a barreled weapon must be capable of causing serious bodily injury or death to a person. Canadian courts have accepted the forensically established criteria of "penetration or rupture of an eye" as serious bodily injury. The minimal velocity of nonconventional ammunition required to penetrate the eye including airsoft projectiles has yet to be established. To establish minimal threshold requirements for eye penetration, empirical tests were conducted using a variety of airsoft projectiles. Using the data obtained from these tests, and previous research using "air gun" projectiles, an "energy density" parameter was calculated for the minimum penetration threshold of an eye. Airsoft guns capable of achieving velocities in excess of 99 m/s (325 ft/s) using conventional 6-mm airsoft ammunition will satisfy the forensically established criteria of "serious bodily injury." The energy density parameter for typical 6-mm plastic airsoft projectiles is 4.3 to 4.8 J/cm2. This calculation also encompasses 4.5-mm steel BBs.     

Velocity necessary for a BB to penetrate the eye: an experimental study using pig eyes

PURPOSE: To determine the V-50 threshold velocity needed for a steel BB to penetrate the eye of a 230-pound pig. METHOD: BBs were shot at a distance of 10 feet into the corneas of pig eyes with a pump-action BB gun. RESULTS: The V-50 velocity for corneal penetration and serious disruption of the eye was found to be 246 ft/sec. CONCLUSION: Due to the nearly identical size and anatomy of the human eye to the pig eyes used in this study, it is felt that 246 ft/sec is a reasonable approximation of the velocity needed to penetrate the human eye.     

Calculating the exclusion probability and paternity index for X-chromosomal loci in the presence of substructure

There has been recent interest in the use of X-chromosomal loci for forensic and relatedness testing casework, with many authors developing new X-linked short tandem repeat (STR) loci suitable for forensic use. Here we present formulae for two key quantities in paternity testing, the average probability of exclusion and the paternity index, which are suitable for X-chromosomal loci in the presence of population substructure.