Bullet/Cartridge Analysis

Question 1

what are class characteristics of a bullet

Answer 1

land/grooves impressions (number, depth, width)
twist direction, caliber, shape

Question 2

class characteristics of bullet casing

Answer 2

shape, manufacturer, caliber, composition, extractor/ejector marks, breech face and firing pin

Question 3

what is caliber

Answer 3

approximation of diameter of the bullet

Question 4

what kind of evidence can you pull form a damaaged bullet

Answer 4

DNA and GSR

Question 5

what is a mushroomed bullet

Answer 5

a bullet desgined to expand on impact causing the target more damage

Question 6

what might you need to do to analyze a mushroomed bullet

Answer 6

carefully adjust the bullet shape to look for things

Question 7

what to look for with lands/groove marks

Answer 7

number of lands/groove, measurable lands/grooves, measurement of imporessions

Question 8

what is so different about glocks

Answer 8

they have rounded lands/grooves ie polygonal (0 in measurements)

Question 9

what are adaptors and what are they used for

Answer 9

adaptors are stuck int he barrel to help smaller bullets travel down the barrel easier

Question 10

are adaptors riflied

Answer 10

they may or may not be

Question 11

what are subclass characteristics

Answer 11

where the tools to make items and worn/damaged and the mark is left on the tool is it making

Question 12

what are individual characteristics

Answer 12

they are marks accidentally left by when a tool is used they are unique and a little special

Question 13

what bullet striations

Answer 13

individualizing marks on bullet they are unique to each firearm

Question 14

shawing/shearing

Answer 14

a bullet being cut form a misaligned revolver barrel

Question 15

skid marks:

Answer 15

smudgy rifling being the bullet gets caught and actually gets rifling

Question 16

what are striated action marks and what are some examples

Answer 16

they are microscopic scratches on the case. some exmples are firing pin drag, extractor and ejector marks

Question 17

what is a chamber mark

Answer 17

it is when the explosion int he case causes the case to expand and take the impression of the firing chamber

Question 18

how can you determine if a bullet was shot by a glock

Answer 18

by checking for a square firing pin mark in the breech face (hot cartilage into square pin then impression left)

Question 19

what are impressed action marks and what are some examples

Answer 19

they are marks impressed by a hard hitting object (hammer like movement) some examples are firing pin and breech face marks

Question 20

How to ID a shotgun

Answer 20

best bet is finding the shell and looking for marks there

Question 21

how do you compare lab samples

Answer 21

you compare known and unknown

Question 22

how can you obtain the known samples

Answer 22

water tank: possible damage when collected
bullet catcher: non-flammable fiber, undamaged bullets
indoor firing range: to test for GSR, no bullet recovery

Question 23

what is the cibin database

Answer 23

the Canadian integrated ballistic identification system, compares bullet info across the country and NIBIN

Question 24

Comparison conlusions part 1

Answer 24

1. no value: no visible evidence of bullet, nothing to properly analyze
2. of value: has enough evidence to analyze

Question 25

comparison conclusions part 2

Answer 25

1. exclusion: class characteristics don’t match
2. insufficient support for exclusion: class matches but individual don’t match
3. insufficient support for either: class matches but not enough KNM
4. insufficient support for ID: class match and most individual match’s
5. ID: class match and ALL individuals match

Question 26

what might be hard about guns in a cold case

Answer 26

damage and wear+tear in the gun over time changing the striations