Midterm

Question 1

Primitive firearms

Answer 1

firearms prior to firearms being able to shoot rimfire

Muzzleloaders

handcannons
matchlock
wheellock
flint lock
percussion caps
pinfire

Question 2

Cycle of fire: in order

Answer 2

cocking
feeding
chambering
locking
firing
obturation
unlocking
extraction
ejection

Question 3

matchlock

Answer 3

Primitive triggers allow the mechanical firing of guns

ignited by a lit fuse with gunpowder placed in a flash pan. the lit fuse would ignited the flash pan which ignited the main powder charge

pros- first trigger, pretty accurate comparatively

cons- fragile, weather sensitive, poor accuracy
Had to keep match lit the entire time

Question 4

wheellock

Answer 4

Bring us to more modern times and away from the idea that we needed fire with us to light a fuse (Use flint and steel to create spark)

Think of cigarette lighters
Flint and steel ignition

Very expensive and not prime for mass production or for armies, only very wealthy land owners could afford to have these made

Pros – shorter dwell time, better accuracy, less weather sensitive
Cons – fragile operating system, very expensive to manufacture

Question 5

flint lock

Answer 5

flint striking ignition mechnism

cheap to produce, relatively fast reloads

cons- blackpowder, lots of smoke

Question 6

percussion caps

Answer 6

where colt started

Pros – cheap, faster lock/ dwell time, improved weather resistance, multi-shot repeater action, super long reload
Cons – slow reload time, possible sympathetic detonations

Little cup looking things with pressure sensitive explosives the bottom
Sits on the post of a breech cap (nipple)
This gives it the spark

Fired caps split (3s or 4s)
Look for the nipple to see if percussion caps

Pepper box
Gave ability for multiple shots before having to reload, this is why percussion caps are so important
They gave us the force multiplier of repeating firearms (a fa that can hold more than 2 shots adn fire before having to reload)

Question 7

Pinfire

Answer 7

Off set primer
Firing pin part of cartridge

Important for the same reason wheellocks are important. What it did was show you what was possible
This gave us an early cartridge

Primer and percussion cap
90 degree angle that had to be worked with
90 degree firing pin that is part of the cartridge

Look for the chamber cutout that allows for this type of cartridge to ID this type of gun

Made of copper
Notoriously unreliable
Corrosion of ammo
This is the end of/ the start of the primitive firearms that show up regularly at crime labs

Question 8

Cocking

Answer 8

rearward movement of the slide forces the hammer back, slide moves over the hammer and the revoil spring becomes compressed again, firearm has been given spring tension to start the firing process over again, the slide moves forward, beginning the firing process again

Question 9

Feeding

Answer 9

cartridge is inserted into the firearm, this can be done manually or from the use of magazines or clips

Question 10

Chambering

Answer 10

cartridge is inserted into the chamber and fully aligned with the boly face. The cartridge needs to have the correct measurements to fit the firearm

Question 11

Locking

Answer 11

the bolt of the firearm is “locked” into place, can either be a manual or automatic process, closure is critical to ensure appropriate pressure is maintained, pressure control protects teh shooter from danger, once locked, firearm is ready to fire

Question 12

Firing

Answer 12

the breech of the firearm has been locked, trigger pulled bringinthe hammer rearward. Once the trigger is pulled, it allows the trigger bar to release the hammer, firing pin released to strike the primer. Once the firing pin has hit the primer, the powder burns creating gas and pressure that they send the bullet down the barrel

Question 13

Obturation

Answer 13

the cartridge case is expanded to seal the gases in the barrel. The pressure of this pushes the bullet down the bore of the barrel

Question 14

Unlocking

Answer 14

after firing the slide is moved rearward compressing the recoil spring, this unseats the cartridge case from the chamber, this is coupled with the start of the extraction and ejection process

Question 15

Extraction

Answer 15

think “claw,” the cartridge or spent cartridge case is removed from the barrel of the firearm. Extractor grabs in the extractor groove of the cartridge or cartridge case

Question 16

Ejection

Answer 16

the cartridge or cartridge case is expelled from the firearm. Extraction pulls it from one direction and the ejector punches the cartridge out

Question 17

What marks the beginning of modern firearms?

Answer 17

Rimfire ammo being created, pinfire is the beginning of modern and end of primitive when it comes to the lab

Question 18

What are the two types of firearms?

Answer 18

Handguns and longguns

Question 19

Longguns

Answer 19

In theory designed to be a shoulder fired weapon

Question 20

Handguns

Answer 20

Firearm that is designed in theory to be shot with one hand

semi-auto, revolver, darringer

Question 21

Semi-automatic pistols

Answer 21

most pistols

a magazine-fed handgun that fires one shot per trigger pull, automatically ejecting the spent casing and chambering a new round using energy from the previous shot

Question 22

Revolver

Answer 22

A repeating firearm that has a cylinder with multiple chambers. The cylinder rotates when the trigger is pulled
One shot per function of the trigger

Question 23

Derringer

Answer 23

Most are multi barrel designs

2 completely different barrels, sometimes confuses examiners
Two different breech faces and firing pins, don’t wanna break something you shouldn’t and have the gun go off

Single or multi-shot handguns generally small
Can also be four barrels or more

Question 24

Rifle

Answer 24

Rifles are a shoulder fired firearm with a rifled barrel and fires cartridges

Question 25

Shotgun

Answer 25

Shotgun is smooth barreled shoulder fired that fires shells

Question 26

Disconnecter Test if done how and used for what?

Answer 26

With an empty firearm pull the trigger. Work the action while you have the trigger held rearword. Once the action has been worked, release the trigger and pull it fully rearward. The hammer should fall at this point. If it doesn’t you may have a full auto weapon used to test if semi or full auto machinegun

Question 27

Types of machineguns

Answer 27

open bolt and closed bolt

Question 28

Scientific definition of a firearm

Answer 28

An assembly of a barrel and action from which a projectile(s) is propelled by products of combustion

Question 29

safe action

Answer 29

Combo of both single and double Long trigger pull of double, but stays the same every time and you have to cock it so, striker fired trigger

Question 30

Single action

Answer 30

Capable of only dropping the hammer 3-5 lbs of pressure

Question 31

double action

Answer 31

Capable of cocking and dropping the hammer Up to 12 lbs of pressure

Question 32

Types of shotguns

Answer 32

Pump- After pulling trigger, slide unlocked and shooter can pump the slide to unload Semi-auto- one shot per function of the trigger, some struggle with cycling ammo Over-under- barrels stacked Side by side- barrels next to each other

Question 33

Types of Rifles

Answer 33

Lever Pump Semi-auto Assault Machine Submachine

Question 34

Role of a FA examiner

Answer 34

Serial number restoration Firearm ID Casing ID Operability and malfunction testing Shooting reconstructions NIBIN entry

Question 35

Serial number restoation

Answer 35

Obliterated and/ or altered firearms serial numbers can sometimes be restored Chemical, electrolytic, and magnetic particle inspection are some of the methods used (main)

Question 36

firearm ID

Answer 36

A scientific process of determining whether a bullet or cartridge case was fired from a particular weapon. Get the rest

Question 37

Casing ID

Answer 37

A scientific process of determining whether a bullet or cartridge case was fired from a particular weapon. Get the rest

Question 38

Operability and malfunction testing

Answer 38

Seeing if the recovered firearm works Does it work as intended by the manufacturer Malfunction testing Ie, can it fire without touching the trigger Possibly destructive test Done during an affirmative defense case Can determine the general condition of a firearm and whether the firearm is mechanically functional Can determine whether the firearm was altered to fire in full auto Can be test fired to obtain known specimens for comparison to evidence

Question 39

shooting reconstruction

Answer 39

GSR examinations can determine the approximate distance at which a firearm was fired by testing a specific firearm and ammunition combination at known distances

Question 40

NIBIN entry

Answer 40

entering the information into a system (also IBIS) for identification and link weapons between multiple crime scenes

Question 41

Cartridge

Answer 41

Complete round of ammunition How does it work? Firing pin strikes the primer The primer sends a spark into the case body, igniting the gunpowder The gunpowder burns → goes from a solid to a gas which creates pressure Pressure builds in the chamber until the bullet is forced down the barrel

Question 42

Shotshell

Answer 42

straight-walled cartridge designed for shotguns, typically firing multiple small pellets (shot) or a single solid projectile (slug)

Question 43

Pellets vs. Slug

Answer 43

Slugs have sabot and foster: lead projectiles capable of being fired out of a shotgun. Mostly used for larger game and home defense Shot has toxic (lead) and non-toxic (steel or bismoth): pellets: pellets being shot out of shotguns and capable of spreading upon fire

Question 44

Nominal caliber

Answer 44

Base diameter of bullet, or bullet measured at widest point Only describes the bullet diameter Can be shared by multiple types of cartridges If you pull a bullet out of a body, you can only determine nominal caliber One bullet diameter can be shared in many types of non-compatible cartridges Nominal caliber is not specific Cartridges are not interchangeable Does not tell us what ammo needs to be fed into firearm

Question 45

Specific caliber

Answer 45

All the critical dimensions of a cartridge The precise, measured internal diameter of the barrel's lands or the bullet's diameter

Question 46

Spitzer type

Answer 46

Long and pointy Vast majority of rifle style bullets will have this spitzer type

Question 47

What is the difference between rifle and handgun bullets and why

Answer 47

rifle, Long and pointy for improvements in aerodynamics handgun, short and fat

Question 48

Boat tail

Answer 48

Any place you see rifling on a pristine bullet, that is a safe place to measure accurate tapered base reduce drag, best for precision, long-distance, hunting

Question 49

Rimmed

Answer 49

Lacks extractor groove Case where the rim extends conspicuously beyond the case walls Most commonly found in revolvers

Question 50

Rimless

Answer 50

Still a rim But when you look at it straight from above, can’s see a rim. About even with the case wall Has an extractor groove Found in all kinds of modern ammunition

Question 51

Rebated

Answer 51

Seen with rim significantly smaller than the case wall Want to make a new cartridge but you want it to work on multiple firearms. Increases producers wanting to use your new ammo Allows you to take new cartridge developed and fire in a firearm that was already out there.

Question 52

Bolted

Answer 52

Case that utilizes an extra band of metal at the base webs Why? The region experiences the most amount of stress and pressure. Reenforcing and allowing it to take more pressure Seen mostly in magnum

Question 53

Bottleneck case

Answer 53

Large diameter at base, and at the shoulders it dramatically decreases to the mouth Mostly in rifles, some in pistols

Question 54

straight walled case

Answer 54

Same diameter from case to case mouth

Question 55

Full metal jacket

Answer 55

Most common type of CF ammo Lead that has a thin gilding metal (usually copper), this helps to control where the bullet goes Noted for deep penetration, in .45, usually foes straight through the body Less vaporous lead exposure for the shooter since the smoke is usually from the exposed lead

Question 56

Semi jacketed

Answer 56

Cheaper with most of the benefits of a full metal jacket Fairly decent control, barrel isn’t exposed to lead

Question 57

semi jacketed hollow-point

Answer 57

same benefits, less expensive, used mostly for hunting still upsets and mushrooms when reaches fluid

Question 58

jacketed hollow point

Answer 58

When it reaches fluid, it causes the bullet to upset and mushroom, meaning the diameter will increase significantly They can expand up to 40-50% of the diameter Arguably more humane and better to lessen collateral damages We like jacketed because it is best for the widest variety of scenarios

Question 59

wad cutter

Answer 59

Projectiles optimized to avoid arguments Designed to punch best holes in arguments Therefore almost entirely found in shooting comps or sport/ target ammunition square, straight up and down, flat on top

Question 60

semi wad cutter

Answer 60

Projectiles optimized to avoid arguments Designed to punch best holes in arguments Therefore almost entirely found in shooting comps or sport/ target ammunition mainly flat with little traffic cone hat on it

Question 61

Definition of gauge

Answer 61

Gauge is an english unit of measurement the number of solid lead balls in the diameter of your barrel bore it takes to equal 1 lb

Question 62

What is important to look at at a scene where a shotgun was used

Answer 62

Look at wad and pellets at scene Wad tells gauge and manufacturer Pellets tell shot size and toxic vs. non toxic

Question 63

Forensic science defined

Answer 63

Science as it is applied to the law the application of scientific principles and techniques to matters of criminal justice, specifically regarding the collection, examination, and analysis of physical evidence

Question 64

Why do we care about manufacturing?

Answer 64

Heart and soul of how firearms identification is possible. How we are able to match and ID is directly tied to how they are manufactured. They are unique because of manufacturing use and abuse, that is how we ID

Question 65

NFA categories

Answer 65

Machine guns Short Barreled shotguns Short Barreled Rifles Suppressors/ silencers Destructive Devices Any other weapons

Question 66

Silencers

Answer 66

Any device or functional part thereof that when attached to a firearm that reduces the report of that firearm

Question 67

Measurements for short barrel rifle and definitions

Answer 67

BBL length less than 16” And/or overall length less than 26”

Question 68

Measurements for short barrel shotgun and definition

Answer 68

Barrel legnth less than 18 inches, and over an overall length less than 26

Question 69

NFA "like" items that are NFA

Answer 69

Don't meet the definition of machine guns rapid fire triggers bump firing bumpstocks binary triggers Gatling gun Dillon minigun

Question 70

Steps of making a barrel

Answer 70

Deep hole drilling Reaming Lapping Straightening Rifling (4 types) Contouring/ profiling Chambering/ throating

Question 71

Slam fire

Answer 71

Guns goes off once you close the action Defined as a condition that has the firearm discharge once the action has been closed without the operator pulling the trigger Note: some shotguns (e.g. Ithaca pumps) has a “slam fire” feature that allowed the operator to hold the trigger down while pumping the shotgun. This would result in the shotgun firing as soon as the action was closed without the need to release and re-pull the trigger

Question 72

Machine guns defined

Answer 72

Heavy firearms designed for sustained automatic fire Legal term: any firearm capable of firing more than 1 round per pull of the trigger NFA: Any part that turns semi into full counts under here

Question 73

Destructive Devices

Answer 73

Explosives or high capacity shotguns Grenades, canons, etc. Basically a catchall, usually talking about explosives though (artillery pieces, grenade launcher, street sweeper type shotguns)

Question 74

Any other weapons

Answer 74

Typically a term for disguised guns or controlled firearms that don’t fall into any other category of NFA weapons firearms that are disguised

Question 75

Deep hole drilling

Answer 75

**Very forensically significant Drill-but does not spin, the barrel spins, this ensures a straighter hole This is where a ton of the individual characteristics come from (this is why we tour, we want to see the forensic significance of the deep marks and characteristics) Process of putting a hole, roughly the diameter we want, in the barrel Big bite of metal

Question 76

Reaming

Answer 76

Cutting oil flows out of the barrel Removing a very small amount of metal to get the barrel diameter perfect (clean up step) **Forensically significant

Question 77

Lapping

Answer 77

Not seen in commercial, seen in customs helps with performance Taking a rodd and put it in a lead furnace that has sand in it, put a slug on the end of the rod and running it in and out of the barrel until it makes it 100% perfect Takes over an hour and very physically demanding **Because it is done with abrasive impregnated in lead, it leaves marks, thus forensically significant

Question 78

Straightening

Answer 78

Matters for performance, but because it is only happening to the outside of the barrel, it is not forensically significant

Question 79

Rifling

Answer 79

*forensically significant, super important cutting the lands and grooves into the barrel can use: cut rifling, button, electron discharge machining, or hammer forged

Question 80

Contouring/ profiling

Answer 80

Increasing the surface area increases barrels ability to dissipate heat **Contoured muzzles are incredibly forensically significant Recessed muzzles and crowns used for service weapons Scratches on the muzzle can cause a bullet to tumble This is forensically significant because it protects the crown the process of shaping the exterior of a raw barrel blank to a specific diameter, taper, and thickness

Question 81

Chambering and throating

Answer 81

Chambering: This cuts a place for your cartridge case in your barrel Throating: makes room for the bullet Important in order to actually fire ammunition **forensically significant

Question 82

What can make a gun fail catastrophically

Answer 82

Fire, wrong ammunition, reload, squib load, barrel obstruction

Question 83

How to handle an unsafe gun for a test

Answer 83

Remote fire primed case or shell to lower pressure

Question 84

How to render a firearm safe per protocol

Answer 84

Remove the source of the ammo Open the action and do a visual and physical inspection of the chamber Have a 2nd person qualified verify Use a zip tie to prevent the firearm from being loaded and to keep the action open