exam 3 balls

• revolvers can only hold 6 bullets

• conical= cone like pattern

  • phrase is a shotgun effect

• sawed off shotgun- barrel has been cut short(short-barreled

• shotgun gauge measured by gauge, doesnt contain rifling lines inside barrels/ doesnt have the grooves

  • The higher the gauge, the smaller the guns barrel and the less kinetic energy

  • cant rly match up shell to gun bc shell is protected by the sleeve

• Israel Military Industries’ Uzi and the Ingram MAC-10

  • SMG’s use pistol calibers such as 9mm (smaller ones)

  • theyre fully auto (as long as trigger held down it keeps shooting)

  • are considered illegal due to the ability to fire rapidly, and their ability to be easily concealed

• markmanship- someone’s skill in shooting

• stoppingpower- weapons ability to take down a target

• grains= unit for how heavy a bullet is; mass of the projectile not the gunpowder; measured in grams

  • effects accuracy, recoil, and length of travel of the bullet

  • .065 grams

• penetration power- how far a bullet can travel through a surface

  • depends of the weight, speed, type, construction

• caliber- unit of measurement

  • diameter of cylindrical objs

• caliper- tool to measure

  • determines length, width, thickness, depth

• FMJ and FMJBT are both types of ammunition that use a lead core encased in a metal jacket. FMJ stands for "full metal jacket", and FMJBT stands for "full metal jacket boat tail". The main difference between the two is the shape of the rear end of the bullet

Ch 6

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Notes

Chapter 5

• what are the four types of common weapons

  • pistol (magazine, civilians max is 10 or 9 in mag 1 in chamber, if more than 10 = illegal firearm

  • revolver (cylinder/wheel, usually 6

  • rifle (stock, there for stability and switcher to make it from semi to fully auto

  • shotgun (got wood handle) (pump/slide

  • 1,c(bottle neck) rifle

  • ;2,(ring) revolver the bottom is a little bigger to go into the hole

  • 3 (plastic) shotgunn

  • 4 to pistol, (groove/caved in)

  • ammunition 22 (.22)- used by three diff types of weapons (pistol, rifle, revolver), you cant tell what type of weapon, (its cheaper), rim firing (compared to all other ammos called central firing) firing hits on edge makes it harder to match

• revolver

  • doesnt jam since its manual loading

  • takes more time to reload

  • tirigger pull is heavy

• rifle

  • long barreelll

  • more accurate so its more accurate

  • ar 15 (no more than 10 rounds)

  • and M 16 (millitary

• shotgun

  • shotgun effect one trigger hit a lot of ppl bc of cone shoots a lot of little particles

  • semi auto- one trigger one bullet

• SMG

  • pull trigger shoots a lot in a few second

  • cant buy uzi in US

  • can buy 9 mm legally and use in uzi

  • not designed for accuracy

  • magazine can hold 30 per

  • illegal bc, 30 per mag, has silencer/suppressor, fully auto

• what are the four factors affections function

  1. accuracy

     1. barrel length

        1. rifling

        2. once bullet strts to spin it increases speed and accuracy

     2. sight

        1. laser

     3. markmanship- shooting skill

  2. shooting distance

     1. from barrel to target

     2. caliber - inch, metric, gauge (one lb of lead divide 1lb of lead into 12 units; the bigger the number the bigger diameter, 10 is biggest

        1. common gauges are 10, 12, 16, 20 , 28,

        2. .410-bore is the smallessttt

     3. powder 4 diff types

  3. stopping power

     1. shape round hollowpoint

  4. penetration

  • firing pin gives 30% info on what gun shot it

  • bridge face hits center; harder to tell

  • officer involved shooting

    • gun policy for officers- shoot to kill

    • tenesse v gardner 1984

firing pin top right corner

ejector is bottom enter the back part not the cilindrical one

breech face wall of the bottom chamber

• fired v unfired bullet

  • if primer is flat its unfired

  • if theres a hole/indintation its fired

  • lines on bullet

  • inside of bullet always made of lead

  • fully/semi/hollow point bullets what the diff?

• Luger- ammunition

• Ruger- weapon

• video questions

  • .380 calliber (cheap pistol)

    • if .38 (revolver;super-pistol)

  video questions

  • had stippling(residue/black dots that is unburned gunpowder) on gunshot wound

    • stpplingg shows when its close range

  • found car in ditch( secondary location)

    • glass chips on ground- shooting occured there

  • belongings were still in the car so the motve wasnt robbery

  • whats diff between motive and intent

    • motive- idea

    • intent- reason why crime was commited

  • act intent and relationship

Ch 6

• bullet consisits of jacketing,, calliber, rifling, and grain

• rifling makes bullet spin increasing speed and accuracy ; lowkk counters gravity ; bullets are pointy to help w air risistance

• cut part called groves uncut parts are called lands (they must be equal min=4 max=8)

• the grooves of barrel must correspond to the lands of the bullet and land of bullet corresponds to the grooves on bullet

• right twisted guns are most common

• lines direction on bullet determine right v left twisted

• automated ballistics comparison

  • Nataional integrated ballistic information network- by atfe

    • big computer database stores images of microscoptic marks on surfaces of fired cases and bullets

    • equal to IAFIS

    • national program

  • Integrated ballistics identification system

    • contracted companies (measuring algorithm) by police crime labs nationwide

    • IBIS is computer tech taking pics of surfaces at a terminal and send pics to database

    • NIBIN IS A LE (law enforcement?) database

    • there are 222 sites of law enforcement by NBIN on cases/bullet

      • 60-70% accuracy

      • should improve color; statistics; 3d images

    • glocks produce rectangular firing pin mark

    • illegal weapons

      • extended stock

      • foregrip

      • shorter barrel on rifle

      • silencer

      • stabilizing brace

$\color{#967bb6}\rule{4000px}{2px}$Summary

1. refreactive index test

   • crush known and unknown

   • put in oil and heat oil

   • heat it till disapears like 70 degrees

   • if both disapear both unknown and known are similar

• second test(?) there was nine

1. two evidence was telephone record and cigarette butt they got saliva dna from lipstick secret third was dna/fingerprints on phone

2. what incriminating evidence they used to arrest the man from outside there was a tiny bloodstain belonging to doug miller

3. blood on crewneck blelonging to doug miller

4. three questions you can challenge in the case - eyewitnesses? how come doug millers skin cell was underfringertips if the other guy had gloves, no gun found to link him, what was his motive/intent

   caliber

   • inch; mm; gauge

5. caliper

   • tool for measurement

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Notes

Direction- clockwise or counter scratchess

Number- how many lands and grooves

width- of groove in barrel to land on bullet etc

ratio-

• bullet weapon connection

  • land inside barrel produces groove on barrel

  • there are equal numbers of lands and grooves inside barrel

  • the width of land inside barrel must b equal to grooves of bullet

6R- six lands and grooves right twisted (clockwise)

4L- 4 lands and grooves left twisted (counter clockwise)

• lab examination by striation

  • tiny lines on bullet naked to visible eye

  • use compound microscope to compare the striations

  • need 6 to be in agreement for them to match

  • steps

    • examine fire and suspected bullet with known sample by test fire using compound comparison microscope

    • compare by cliber/caliper

    • determine twist direction

    • count num of lands and grooves

    • widths of two lands

    • widths of two grooves

    • rotates to locate 6 striations

• Bullet shape and angle + surface

  • a- intact fired on soft surface

    • bullet doesnt become distorted/mishaped

  • b- ricocheted- low angle (30 below) on hard surface

    • used to determine shooter position

  • c- mushroomed- at 90degree onto hard surface

  • d- fragmental- at 90deg onto hard surface w/ short distance