Firing distance estimates with pellet dispersion from shotgun with various chokes: an experimental, comparative study

There are several studies suggesting models for firing distance estimation due to pellet dispersion, but few of them consider the degree of choke of a shotgun. The purpose of this research is to suggest some models for estimation of the firing distance for choked and cylinder bore shotguns. Twelve gauge with full chokes, and 12 and 16 gauge with cylinder bore shotguns were fired with #2 and #5 shots from 75, 100, 300, 500, and 1000 cm distances. Statistically significant pellet dispersion values were found for each shotgun by using #2 and #5 shots for different firing distances. All the data obtained were analyzed with linear regression and four models were constituted. Investigators should use special formulae for each shotgun, degree of choke, and pellet type while determining the firing distance. Therefore, more experimental and comparative studies should be designed for each type.     

Comparison of the Class and Individual Characteristics of Turkish 7.65 mm Browning/.32 Automatic Caliber Self‐Loading Pistols with Consecutive Serial Numbers

Abstract: Firearms identification is based on the fundamental principle that it is impossible to manufacture two identical items at the microscopic level. As firearm manufacturing technologies and quality assurance are improving, it is necessary to continually challenge this principle. In this study, two different makes of 7.65 mm Browning/.32 Automatic caliber self‐loading pistols of Turkish manufacture were selected and examined. Ten pistols with consecutive serial numbers were examined and each fired 10 times. The fired cartridge cases were recovered for comparison purposes. It was found that for each make of pistol, the individual characteristics within the firing pin impression, ejector, and breech face marks of all 10 pistols were found to be significantly different.     

Sequential angulation,spatial dispersion and consistency of distance attack patterns from home in serial murder,rape and burglary

Abstract

Three related measures of spatial movement (sequential angulation, spatial dispersion and consistency of distance in attack target) were compared across three serial offence types: serial homicide (n=35), serial rape (n=41) and serial burglary (n=30). In each case, each offender had committed at least five offences. “Spatial dispersion”, defined as the extent to which an offender distributes his offences across either a focused or relatively more evenly distributed area, revealed that burglary was less evenly distributed (i.e. more focused) than rape and murder. “Sequential angulation”, defined as the degree of rotational movement around the home of the offender from one offence to the next, revealed that serial murderers have higher angulation scores than do rapists who, in turn, have higher angulation scores than burglars. Lastly, a comparison of the offender's consistency in the relative distance travelled from home to each attack site (“consistency of distance in attack target”) was relatively similar across the three groups. This was despite the comparison of different serial offence types from disparate geographical areas. The supposition that differences in dispersion and sequential angulation scores across crime types are related to the perceived risk of the crime has been confirmed. The specificity and the mobility of the targets are also discussed.     

美国多元主义政体成因探析

美国的政治过程是由一批权力中心的运作来体现的美国是典型的多元主义政体国家，这一强调个人和公民社会权利的政治体制表现为权力中心的多元化。多元主义政体在美国的形成不是偶然的，而是由美国独特的历史背景、自由主义的政治哲学、人们对纯粹民主政治可能导致弊端的担心以及美国利益多元化等多方面因素决定的。了解美国政治本质特征及其成因，有助于我们认识美国政治和美国政府的决策过程。     

Blind Spots: The Effects of Information and Stakes on Fairness Bias and Dispersion

Mounting empirical research provides evidence of fairness bias and its economic and social effects, where fairness bias refers here to a deviation of claims from unbiased justice due to a personal stake. A far less appreciated issue is dispersion of fairness views and claims, which is also important for its effects on disagreements, empirical analysis, and philosophical theories. This study undertakes a systematic analysis of the effects on fairness bias and dispersion of two variables: stakes and information. Most philosophical and social science analyses related to justice and bias associate heightened bias with increased information and, conversely, impartiality with the elimination of certain information. Less attention has been paid to the opposing impact of information, which is to supply the facts needed to achieve justice more reliably. An important open question is whether, on balance, increased information helps agents to achieve fairer outcomes or whether biased use of such information contributes to less fair outcomes. This study focuses on a set of previously reported experiments that share certain features and subjects them to a new analysis. The results of this analysis suggest that, although information is often used in a self-serving way, increased information can, under certain conditions, contribute to fairness claims becoming less biased and less dispersed, both for stakeholders as well as impartial spectators.     

加强手枪射击教学实用性训练 提高学员的实战能力

目前,射击虽作为全国公安院校学员的必修课,大部分的射击教学都是以基础知识和基本技能训练为主,并不注重实战能力的训练,而我们培养的学员今后要使用手中的武器去与犯罪分子进行殊死搏斗。因此,提高学员的实战能力就成为我们手枪射击教师的当务之急。提高学员的实战能力,就要加强近距离快速射击训练;利用地形地物的射击训练;多目标选择性的射击训练;快速重新装弹训练;反应性射击训练。     

应用比对显微照相检验59式手枪射击弹头撞击金属后的痕迹价值

射击弹头碰撞不同客体产生的变形损伤程度存在差异。利用比对显微镜,进行无变形损伤射击弹头和变形损伤射击弹头的痕迹比对照相,来论证59式手枪射击弹头撞击金属后痕迹特征的稳定性和对鉴定价值的影响,可以为变形损伤射击弹头痕迹检验提供科学依据。     

一例枪支走火案件的分析检验步骤和方法

在实践中,我们经常会碰到由于枪支走火、跳弹等致人死亡的意外事件,对此类案件的分析、检验往往有一定的难度,特别相隔较长一段时间后,许多信息随着时间的流逝而不能加以充分利用时。所以对此类案件该如何利用有限的资源信息以准确认性,这是非常关键的问题。本文结合一具体案例,提出对此类案件进行分析检验的步骤和方法。     

谈人民警察手枪射击的教与学

提高学员射击技能,是公安院校教师在教学和训练中的主要任务。但是,从近年教学实践中反映出的情况来看,要使学员准确地掌握手枪射击的动作要领,提高学员的射击技能,并非易事,尤其在短时间内,使学员掌握射击要领的确很难。文章从规范化的角度,对警用手枪射击教学方法进行了研究,以期对公安院校师生手枪射击的教与学有所裨益。     

用微积分法对非制式枪弹痕迹诸元的检验分析

对于制式枪弹痕迹的研究已有很多,但实际工作中对于非制式枪弹痕迹诸元的分析可依据的相关资料不多,现利用微积分法对其检验与分析,从而更好对侦察、破案发挥有利线索及证据作用。