1. BALLISTICS AND FIREARMS
MCCONNELL

2. FIREARMS IDENTIFICATION
DISCIPLINE MAINLY CONCERNED WITH DETERMINING WHETHER A BULLET OR CARTRIDGE WAS FIRED BY A PARTICULAR WEAPON
INCLUDES:
BULLET COMPARISON
WEAPON OPERATION
SERIAL NUMBER RESTORATION
GUNPOWDER DETECTION & CHARACTERIZATION
ESTIMATING MUZZLE/TARGET DISTANCE

3. HOW BULLET STRIATIONS FORM:

4. HOW BULLET STRIATIONS FORM:
HOLLOW OUT PIECE OF STEEL TO FORM BARREL LEAVING BEHIND MICROSCOPIC DRILL MARKS ON INSIDE OF BARREL OR BORE.
THESE MARKS ARE AS UNIQUE TO THAT GUN AS FINGERPRINTS ARE TO A HUMAN

5. HOW BULLET STRATIONS FORM:
THE BARREL IS THEN RIFLED
RIFLING: THE IMPRESSING OR CUTTING OF GROOVES ON THE INNER SURFACE OF A BORE
THESE GROOVES GUIDE THE BULLET THROUGH THE BARREL CAUSING A SPIRAL/SPINNING MOTION TO KEEP THE BULLET FROM TUMBLING
TUMBLING: THE ROLLING OR TURNING END OVER END MOVEMENT
CALIBER: THE MEASURED DIAMETER OF A BORE

6. METHODS OF RIFLING ROTATING STEEL HOOK CUTTERS BROACH CUTTER
BUTTON PROCESS
MANDREL RIFLING HAMMER FORGING

7. RIFLING LANDMARKS LANDS GROOVES
THE RAISED PORTION OF THE SPIRAL CUTS MADE BY RIFLING
GROOVES
THE VALLEYS OF THE SPIRAL CUTS MADE BY RIFLING

8. THE CHARACTERISTICS OF BULLETS
CLASS CHARACTERISTICS:
ONCE A MANUFACTURER CHOOSES A METHOD TO MAKE A GUN THEY STICK WITH IT.
EX. 5 LANDS, 5 GROOVES, LEFT
INDIVIDUAL CHARACTERISTICS:
THE UNIQUE STRIATIONS ON THE BORE FROM THE DRILLING PROCESS

9. HOW DO YOU COMPARE BULLET MARKINGS?
HAS TO BE DONE WITH BULLETS FIRED INTO WATER OR SOFT COTTON
FIRST ELIMINATE ALL POSSIBILITIES USING CLASS CHARACTERISTICS WHICH IS DONE BY COUNTING THE NUMBER OF LANDS AND GROOVES AND THE DIRECTION OF THE SPIRAL

10. HOW DO YOU COMPARE BULLET MARKINGS?
THEN USE A COMPARISON MICROSCOPE TO EXAMINE THE STRIATIONS FOR INDIVIDUAL CHARACTERISTICS. TURN EACH BULLET SIMULTANEOUSLY UNTIL YOU FIND AN IDENTICAL WELL DEFINED LAND OR GROOVE. THEN TURN THE BULLETS UNTILYOU FIND AREAS OF MATCHING STRIATIONS.
ROTATE TO VIEW ALL IDENTICAL AREAS.

11. PROBLEMS WITH BULLET IDENTIFICATION:
BULLETS ARE OFTEN DAMAGED OR ALTERED TO THE POINT THAT FINDING A COMPLETE PERFECT MATCH IS VERY DIFFICULT.
STRIATION MARKINGS CAN CHANGE IN A GUN OVER TIME FROM WEAR AND TEAR
NO RULE FOR NUMBER OF POINTS OF COMPARISON

12. PROBLEMS WITH BULLET IDENTIFICATION
OFTEN HAVE A BULLET WITH NO WEAPON. BUT CAN BE SOLVED IF THE WEAPON IS VERY DISTINCTIVE.
SHOTGUNS HAVE SMOOTH BARRELS WHICH LEAVE NO CHARACTERISTIC MARKINGS.

13. GENERAL RIFLING CHARACTERISTIC FILE
RUN BY THE FBI
CONTAINS A LIST OF CLASS CHARACTERISTICS FOR ALL KNOWN WEAPONS
PERIODICALLY UPDATED AND SENT TO ALL LOCAL LAW ENFORCEMENT GROUPS

14. PARTS OF A GUN ***GO OVER HANDOUT
CARTRIDGE CASES: THE CASE OR SHELL THAT SURROUNDS THE BULLET
BREECHBLOCK: THE REAR PART OF A FIREARM BARREL

15. ACT OF FIRING: HOW DOES A GUN WORK?
PULL THE TRIGGER TO RELEASE THE WEAPON’S FIRING PIN
THE PIN STRIKES THE PRIMER WHICH IGNITES THE POWDER
GASSES FROM THE BURNING POWDER FORCE THE BULLET FORWARD THROUGH THE BARREL
THIS SIMULTANEOUSLY PUSHES SPENT CARTRIDGES BACKWARD AGAINST THE BREECHBLOCK

16. MARKS ON CARTRIDGE CASES (WHAT CAN WE SEE?)
SHAPE OF FIRING PIN IMPRESSED INTO THE METAL OF THE PRIMER
BACKWARDS MOVEMENT IMPRESSES CARTRIDGE WITH SURFACE MARKINGS OF THE BREECHBLOCK
MARKS FROM THE EXTRACTOR
MECHANISM THAT WITHDRAWS CARTRIDGE FROM CHAMBER

17. MARKS ON CARTRIDGE CASES (WHAT CAN WE SEE?)
MARKS FROM THE EJECTOR
MECHANISM THAT THROWS CARTRIDGE FROM THE FIREARM
MARKS ALSO FORM ON SHOTGUN SHELLS BUT THEY ARE UNLIKE BULLET MARKS

18. AUTOMATED FIREARMS SEARCH SYSTEMS
DRUGFIRE
EARLY SYSTEM DEVELOPED FOR FBI
EMPHASIZED MARKINGS ON CARTRIDGE CASINGS & SOME BULLET STRIATIONS
LOOKED AT IMAGES THROUGH A MICROSCOPE ATTACTED TO A VIDEO CAMERA

19. AUTOMATED FIREARMS SEARCH SYSTEMS
INTEGRATED BALLISTIC IDENTIFICATION SYSTEM (IBIS)
SYSTEM DEVELOPED FOR THE ATF
FOCUSED ON FEATURES FROM EXPENDED BULLETS AND CARTRIDGE CASINGS
USED PICTURES FROM DIGITAL MICROSCOPES

20. AUTOMATED FIREARMS SEARCH SYSTEMS
NATIONAL INTEGRATED BALLISTICS INFORMATION NETWORK (NIBIN, 1999)
COMBINE DRUGFIRE AND IBIS TO FORM A COOPERATIVE SYSTEM
DIVIDED SYSTEM JOBS INTO TWO CATEGORIES
COMMUNICATIONS – FBI
SYSTEM SITES - ATF

21. BALLISTIC FINGERPRINTING
GOAL OF NIBIN
A SYSTEM THAT WOULD CAPTURE AND STORE MARKINGS ON BULLETS AND CARTRIDGES TEST FIRED FROM ALL HANDGUNS AND RIFLES BEFORE THEY ARE SOLD
GOAL HASN’T BEEN REACHED YET

22. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
GUNPOWDER RESIDUE
PARTIALLY BURNED AND UNBURNED PARTICLES OF GUNPOWDER DISCHARGED WHEN A WEAPON IS FIRED
DISTANCE DETERMINATION
CALCULATING DISTANCE BETWEEN FIREARM AND A TARGET BASED ON THE DISTRIBUTION OF POWDER PATTERNS OR THE SPREAD OF A SHOT PATTERN

23. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
HANDGUNS AND RIFLES
IF YOU HAVE A WEAPON
COMPARE POWDER RESIDUE PATTERN ON VICTIM’S CLOTHING OR SKIN TO PATTERNS FOUND WHEN FIRING SUSPECT’S WEAPON FROM VARYING DISTANCES AT A TARGET USING THE SAME AMMUNITION

24. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
HANDGUNS AND RIFLES
IF YOU DON’T HAVE A WEAPON
SEARCH FOR RECOGNIZABLE CHARACTERISTICS AROUND THE BULLET HOLE

25. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
CHARACTERISTICS
IF GUN WAS TOUCHING OR LESS THAN AN INCH FROM THE TARGET THEN YOU WILL SEE:
A HEAVY CONCENTRATION OF SMOKELIKE VAPOROUS LEAD SURROUNDING THE HOLE
SCORCH MARKS OR MELTING AROUND THE HOLE

26. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
CHARACTERISTICS
IF GUN WAS TOUCHING OR LESS THAN AN INCH FROM THE TARGET THEN YOU WILL SEE:
STELLATE/STAR-SHAPED TEAR PATTERNS AROUND THE HOLE WHICH ARE FORMED BY BLOW BACK OF MUZZLE GASES

27. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
CHARACTERISTICS
IF GUN WAS GREATER THAN 3 FEET FROM THE TARGET THEN YOU WILL SEE:
NO POWDER RESIDUE AT ALL
BULLET WIPE:
DARK RING AROUND THE PERIMETER OF THE ENTRANCE OF A BULLET HOLE
MADE OF CARBON, DIRT, LUBRICANT, PRIMER RESIDUE, AND LEAD

28. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
CHARACTERISTICS
IF GUN WAS INCHES FROM THE TARGET THEN YOU WILL SEE:
A HALO OF VAPOROUS LEAD
IF GUN WAS UP TO 25 INCHES FROM THE TARGET THEN YOU WILL SEE:
SPECKS OF UNBURNED OR PARTIALLY BURNED POWDER

29. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
WHEN THE WEAPON IS A SHOTGUN
IF YOU HAVE A WEAPON THEN DISTANCE IS DETERMINED BY FIRING THE SUSPECT WEAPON FROM VARYING DISTANCES USING THE SAME TYPE OF AMMUNITION
LOOK FOR SIMILARITIES IN THE SHOT PATTERNS

30. HOW CAN YOU TELL HOW FAR AWAY THE GUN WAS?
IF YOU DON’T HAVE A WEAPON
FIRED FROM UP TO 4-5 FEET FROM THE TARGET, THE SHOT ENTERS AS A CONCENTRATED MASS WITH A HOLE LARGER THAN THE BORE
USUALLY THE SHOT SPREAD INCREASES 1 INCH FOR EACH YARD OF DISTANCE
CHOKE: INTERIOR CONSTRICTION PLACED NEAR THE MUZZLE OF A SHOTGUN BARRELL TO CONTROL SHOT DISPERSION, GREATER CHOKE EQUALS LESS SPREAD

31. HOW DO I LOCATE POWDER RESIDUE ON GARMENTS?
VISUAL EXAMINATION – CAN I SEE IT WITH MY NAKED EYES?
INFARED EXAMINATION – CAN I SEE IT WITH AN INFARED CAMERA/TOOL?
CHEMICAL EXAMINATION – DO CHEMICAL TESTS PICK UP ANY TRACES OF POWDER?

32. HOW DO I LOCATE POWDER RESIDUE ON GARMENTS?
GREISS TEST
CHEMICAL TEST USED TO DEVELOP PATTERNS OF GUNPOWDER RESIDUE AROUND BULLET HOLES BY DETECTING THE PRESENCE OF NITRATES

33. PRIMER RESIDUE THE UNUSED PORTION OF PROPELLANT DURING A GUNSHOT
CAN BE DETECTED IN SEVERAL WAYS
USED TO FOCUS ON NITRATES BUT NOW FOCUSES ON BARIUM AND ANTIMONY

34. DETECTING PRIMER RESIDUE
DERMAL NITRATE TEST – EARLY TEST, PAINTED SUSPECT’S HAND WITH HOT WAX, LET IT DRY, TEST IT WITH DIPHENYLAMINE, BLUE MEANS POSITIVE, BUT GAVE MANY FALSE POSITIVES FOR THINGS LIKE FERTILIZER
ADHESIVE – USES TAPE OR ADHESIVES TO REMOVE ANY PARTICLES OF PRIMER RESIDUE FROM SUSPECT’S HAND WHICH ARE THEN TESTED IN A LAB.

35. DETECTING PRIMER RESIDUE
SWABBING – SWAB BOTH HANDS OF SUSPECT WITH 5% NITRIC ACID SOLUTION, PROBLEM IS RESIDUE COMES OFF EASILY AND SO MIGHT HAVE RUBBED OFF ALREADY
SEM TESTING – USES MICROSCOPE CONNECTED TO AN X-RAY ANALYZER TO LOOK FOR DISTINCTIVE PARTICLES, VERY TIME CONSUMING AND EXPENSIVE

36. DETECTING PRIMER RESIDUE
NEUTRON ACTIVATION ANALYSIS – USES A NEUTRON SOURCE TO LOCATE AND IDENTIFY THE ELEMENTS IN PRIMER RESIDUE, VERY EXPENSIVE, LIMITED, AND STRICTLY CONTROLLED BY THE GOVERNMENT
FLAMELESS ATOMIC ABSORPTION SPECTROPHOTOMETRY – TEST BASED ON HOW DIFFERENT COMPOUNDS ABSORB LIGHT

37. SERIAL NUMBER RESTORATION
WHEN THE SERIAL NUMBER OF A GUN HAS BEEN FILED OFF
SERIAL NUMBERS ARE STAMPED INTO THE METAL BODY OR FRAME
CAN RESTORE BY CLEANING, POLISHING AND THEN APPLYING AN ETCHING AGENT

38. HOW TO COLLECT FIREARM EVIDENCE:
HOLD FIREARM BY TRIGGER GUARD OR GRIP
MAKE SURE WEAPON IS UNLOADED WITH POSITION AND AMMO RECORDED
MARK CHAMBER POSITION WHERE IT LINES UP WITH BARREL
PLACE EACH ROUND/MAGAZINE IN SEPARATE CONTAINER AFTER CHECKING FOR FINGERPRINTS

39. HOW TO COLLECT FIREARM EVIDENCE:
COMPLETE AN EVIDENCE TAG
SERIAL NUMBER
MAKE
MODEL
INVESTIGATOR’S INITIALS
FOLLOW CHAIN OF CUSTODY

40. HOW TO COLLECT AMMUNITION EVIDENCE:
PROTECT ALL CLASS AND INDIVIDUAL CHARACTERISTICS
SCRIBE BULLETS, CASING AND SHELLS WITH INVESTIGATOR’S INITIALS AT EITHER THE BASE OR NOSE
WRAP BULLET IN TISSUE PAPER BEFORE PACKAGING IT FOR THE CRIME LAB

41. HOW TO COLLECT AMMUNITION EVIDENCE:
LEAVE ALL TRACE MATERIALS ON BULLET
NOTE EXACT LOCATION WHERE ALL CASINGS WERE FOUND

42. HOW TO COLLECT GUNPOWDER EVIDENCE:
PRESERVE ALL CLOTHING
PLACE IN SEPARATE PAPER BAGS
AVOID CUTTING OR TEARING AROUND THE HOLE
AIR DRY WET CLOTHES OUT OF SUNLIGHT

43. TOOLMARKS
ANY IMPRESSION, CUT, GOUGE OR ABRASION CAUSED BY A TOOL COMING INTO CONTACT WITH ANOTHER OBJECT

44. COMPARING TOOL MARKS
USUALLY PROVIDES GOOD CLASS CHARACTERISTICS BUT SELDOM GIVES INDIVIDUAL CHARACTERISTICS
CLASS: TYPE OF TOOL, MAKE, MODEL
INDIVIDUAL: DAMAGE ON TOOL