OEC Final Written Test
List Cooper's 4 rules of firearm safety
a. Always treat a gun as if it's loaded
b. Always point the muzzle in a safe direction
c. Always keep your finger off of the trigger until you are ready to fire
d. Always be sure of your target
With regards to safety, what 3 things should be checked prior to test firing a firearm?
a. Check that the bore is clear of obstructions
b. Make sure firing pin and trigger cycle through (dry fire)
c. Check for any alterations made to the gun
Where in the lab is it acceptable to introduce live ammunition to a firearm?
Range or in the tank room (specifically in the port hole of the tank)
What is the maximum number of cartridges loaded during initial test firing?
3
An examiner loads the magazine of a Colt 1911 .45 Auto pistol and inserts it into the magwell with
the slide locked back on the firearm. When they drop the slide to chamber the cartridge, the gun
fires. What are three possible causes of the malfunction?
a. Inadequate headspace
b. A firing pin that has stuck and failed to retract
c. A primer that is either inadequately seated or overly sensitive
Define squib load. Why is this a safety concern?
When a cartridge does not have enough velocity or sound to push the projectile out of the gun.
This can cause a bore obstruction, leading the barrel to bulge or burst from excessive pressure.
When test firing a pistol in the water tank you experience a failure to extract, how do you
proceed?
Keep the firearm pointed in a safe direction (in the port hole) and remove the magazine, rack the
slide, try to diagnose the problem and then start over.
What is the minimum number of test fires required for comparison?
3
Give two definitions of caliber
a. The diameter of the circle formed by the tops of the lands of a rifled barrel
b. The size of a cartridge that the gun was specifically chambered for.
What are the 3 main ingredients of black powder? What is the ratio of those ingredients?
a. Potassium nitrate- 75%
b. Charcoal- 15%
c. Sulfur- 10%
What do Fg, FFg, FFFg, and FFFFg mean regarding black powder? Name a common use for each.
,a. The size of the granules of black powder.
b. Fg- cannons and large bore muskets
c. FFg- medium muskets and rifles
d. FFFg- smaller rifles and most handguns
e. FFFFg- priming flintlock firearms
What is Pyrodex? Describe any advantage to using it over what it replaced.
a. Synthetic black powder
b. Produces less smoke that black powder
c. Is a class B explosive
d. Easier/safer to transport
Describe the primary differences between double base and single base powder
a. Double base powder is composed of nitrocellulose and nitroglycerine
b. Single base powder is only nitrocellulose
List the 3 components of a primer and describe the function of each
a. Cup- holds the primer mixture in the cartridge
b. Anvil- provides a surface for the priming mixture to hit when the firing pin strikes the primer
c. Explosive mixture- provides the initial spark or flame and needed components to ignite the
powder.
Berdan primer
Generally have two flash holes and are not reloadable. The anvil is constructed into the case.
Boxer Primer
Generally have one flash hole and are reloadable. The anvil is a part of the cap.
List 3 lock types in muzzle loaders
a. Matchlock
b. Wheellock
c. Flintlock
What allowed for the most development in repeating firearms?
Percussion Cap
What is a cannelure? Name 3 uses.
a. A circumferential groove around a bullet.
b. Crimping, lubrication, and identification.
What cartridge component would you find fulminate of mercury and potassium chlorate and what
problems did these chemical compounds cause?
These would be found in the primer. Fulminate of mercury caused brass cartridges to become
brittle and was corrosive to the barrel. Potassium chlorate broke down into salt and rusted the
bore of the barrel
What chemical compound is currently used in primers to initiate primer detonation?
Lead styphnate
How many grains are in a pound?
, 7,000
The portion of the bullets outer surface that comes into contact with the interior surface of the
barrel is known as what?
Bearing surface
Explains what classifies a specific cartridge as being a rimfire?
The primer is in the rim of the cartridge.
What rimfire cartridges cam be fired in a weapon chambered for .22 LR?
a. .22 short
b. .22 long
c. .22 long rifle
What features generally allows you to differentiate between a .22LR bullet and a .22 magnum
bullet?
Magnums have a jacket
Who is SAAMI and what do they do?
Sporting Arms and ammunition manufacturing institute, Provides standards for ammunition,
firearms and their components
Which cartridges were the following derived from?
a. .17 HMR- .22 Winchester Magnum
b. .17 HM2 (Mach II) cartridges- .22 LR
Ogive
the curved forward part of the bullet
Obturation
The bullet seals against the chamber when fired
Bearing surface
The part of the bullet that touches the rifling
Primer
The component that sparks an initial flame to get gases to go through the flash hole to ignite the
powder
Cartridge
A single unit of ammunition comprised of a case, gun powder, primer, and bullet
Headstamp
On the bottom of a cartridge case. Provides manufacture and caliber information
Hollow point bullets
Bullet that is hollow in the middle designed to expand on impact
Copper washed lead bullet
Solid lead bullet covered in a copper wash
Wildcat rimfire
.22 Winchester
List Cooper's 4 rules of firearm safety
a. Always treat a gun as if it's loaded
b. Always point the muzzle in a safe direction
c. Always keep your finger off of the trigger until you are ready to fire
d. Always be sure of your target
With regards to safety, what 3 things should be checked prior to test firing a firearm?
a. Check that the bore is clear of obstructions
b. Make sure firing pin and trigger cycle through (dry fire)
c. Check for any alterations made to the gun
Where in the lab is it acceptable to introduce live ammunition to a firearm?
Range or in the tank room (specifically in the port hole of the tank)
What is the maximum number of cartridges loaded during initial test firing?
3
An examiner loads the magazine of a Colt 1911 .45 Auto pistol and inserts it into the magwell with
the slide locked back on the firearm. When they drop the slide to chamber the cartridge, the gun
fires. What are three possible causes of the malfunction?
a. Inadequate headspace
b. A firing pin that has stuck and failed to retract
c. A primer that is either inadequately seated or overly sensitive
Define squib load. Why is this a safety concern?
When a cartridge does not have enough velocity or sound to push the projectile out of the gun.
This can cause a bore obstruction, leading the barrel to bulge or burst from excessive pressure.
When test firing a pistol in the water tank you experience a failure to extract, how do you
proceed?
Keep the firearm pointed in a safe direction (in the port hole) and remove the magazine, rack the
slide, try to diagnose the problem and then start over.
What is the minimum number of test fires required for comparison?
3
Give two definitions of caliber
a. The diameter of the circle formed by the tops of the lands of a rifled barrel
b. The size of a cartridge that the gun was specifically chambered for.
What are the 3 main ingredients of black powder? What is the ratio of those ingredients?
a. Potassium nitrate- 75%
b. Charcoal- 15%
c. Sulfur- 10%
What do Fg, FFg, FFFg, and FFFFg mean regarding black powder? Name a common use for each.
,a. The size of the granules of black powder.
b. Fg- cannons and large bore muskets
c. FFg- medium muskets and rifles
d. FFFg- smaller rifles and most handguns
e. FFFFg- priming flintlock firearms
What is Pyrodex? Describe any advantage to using it over what it replaced.
a. Synthetic black powder
b. Produces less smoke that black powder
c. Is a class B explosive
d. Easier/safer to transport
Describe the primary differences between double base and single base powder
a. Double base powder is composed of nitrocellulose and nitroglycerine
b. Single base powder is only nitrocellulose
List the 3 components of a primer and describe the function of each
a. Cup- holds the primer mixture in the cartridge
b. Anvil- provides a surface for the priming mixture to hit when the firing pin strikes the primer
c. Explosive mixture- provides the initial spark or flame and needed components to ignite the
powder.
Berdan primer
Generally have two flash holes and are not reloadable. The anvil is constructed into the case.
Boxer Primer
Generally have one flash hole and are reloadable. The anvil is a part of the cap.
List 3 lock types in muzzle loaders
a. Matchlock
b. Wheellock
c. Flintlock
What allowed for the most development in repeating firearms?
Percussion Cap
What is a cannelure? Name 3 uses.
a. A circumferential groove around a bullet.
b. Crimping, lubrication, and identification.
What cartridge component would you find fulminate of mercury and potassium chlorate and what
problems did these chemical compounds cause?
These would be found in the primer. Fulminate of mercury caused brass cartridges to become
brittle and was corrosive to the barrel. Potassium chlorate broke down into salt and rusted the
bore of the barrel
What chemical compound is currently used in primers to initiate primer detonation?
Lead styphnate
How many grains are in a pound?
, 7,000
The portion of the bullets outer surface that comes into contact with the interior surface of the
barrel is known as what?
Bearing surface
Explains what classifies a specific cartridge as being a rimfire?
The primer is in the rim of the cartridge.
What rimfire cartridges cam be fired in a weapon chambered for .22 LR?
a. .22 short
b. .22 long
c. .22 long rifle
What features generally allows you to differentiate between a .22LR bullet and a .22 magnum
bullet?
Magnums have a jacket
Who is SAAMI and what do they do?
Sporting Arms and ammunition manufacturing institute, Provides standards for ammunition,
firearms and their components
Which cartridges were the following derived from?
a. .17 HMR- .22 Winchester Magnum
b. .17 HM2 (Mach II) cartridges- .22 LR
Ogive
the curved forward part of the bullet
Obturation
The bullet seals against the chamber when fired
Bearing surface
The part of the bullet that touches the rifling
Primer
The component that sparks an initial flame to get gases to go through the flash hole to ignite the
powder
Cartridge
A single unit of ammunition comprised of a case, gun powder, primer, and bullet
Headstamp
On the bottom of a cartridge case. Provides manufacture and caliber information
Hollow point bullets
Bullet that is hollow in the middle designed to expand on impact
Copper washed lead bullet
Solid lead bullet covered in a copper wash
Wildcat rimfire
.22 Winchester
