Block 6 details

Revolver

a firearm with a cylinder having several chambers so arranged as to rotate around an axis.

Anvil

Boxer: priming mixture crushed by the firing pin blow

Rimfire: breech end of the chamber

Crane / yoke

The part of a solid frame revolver on which the cylinder is swung out to the side to accomplish loading and ejecting.

Cylinder

The rotating component of a firearm that contains the chambers.

Cylinder end play / end shake

the free longitudinal movement of the cylinder in the frame of a firearm

Cylinder gap / Cylinder-barrel gap

the maximum space between the cylinder and the barrel

Cylinder alignment

The relationship of the axis of the chamber in a revolver cylinder to the axis of the bore

Cylinder bolt / stop

A device to stop cylinder rotation in proper alignment with the barrel.

Cylinder latch / bolt

A device which permits the swinging out or release of the cylinder from the frame of a revolver.

Cylinder stop notch

One of the machined grooves on the circumference of a revolver cylinder that is engaged by the cylinder stop in order to ensure barrel and chamber alignment.

ejector rod

A rod found on revolvers which is pushed rearward to facilitate extraction/ejection of cartridge cases or shotshells from a cylinder.

Ejector tube

A tube attached to the underside of the barrel of some single action revolvers which contains and guides the ejector rod.

Forcing cone

The tapered entrance to the bore at the breech end of a revolver barrel.

Sear Notch

A notch typically located in the hammer, in which the sear or trigger is held under tension of the mainspring until released by movement of the trigger.

Sear spring

A spring which puts pressure on the sear of a firearm to return the sear to its normal position upon release of the trigger.

Side plate

A removable plate in the frame or receiver of a firearm that allows access to internal parts or upon which some internal parts are mounted.

Loading gate

The hinged piece attached to the frame of revolvers that can be opened to permit loading of the chambers.

Recoil shield

On a revolver, a lateral extension of the standing breech to each side, to prevent fired or unfired cartridges from coming out of the chambers and to protect the otherwise exposed primers of unfired cartridges.

Hammer Notch

One or more grooves on the hammer which engages a firing or safety component such as the sear.

Hammer shroud

A piece added to or a portion of the frame of a revolver to cover the sides of the hammer

Hammer Spur

The knob or extension of an exposed hammer which acts as a cocking/decocking aid.

Rebound slide

A reciprocating device found in some double action revolvers which moves the hammer into a position in which there is no contact of either hammer and firing pin or firing pin and primer (primary safety)

Hammer block

A device which separates the firing pin from the hammer except when the trigger is pulled

Transfer bar

A metal bar connected internally to the trigger which usually reciprocates with the trigger or hammer of a revolver to transfer the energy of the hammer to the firing pin

How do you know a hammer block is working during a function test?

A hammer block should only fall out of the way when the trigger is completely pulled and the hammer falls forward

Rebounding hammer

A mechanism where the hammer automatically retracts slightly to a rest position after causing a cartridge to discharge.

How do you know a rebound hammer is working during a function test?

The hammer will not fully rest on the firing pin unless the trigger is completely depressed

How do you know a transfer bar is working during a function test?

When the hammer is fully cocked, the transfer bar should raise until it completely covers the firing pin

Describe single action in a revolver.

Hammer must be cocked to manually rotate the cylinder, pulling the trigger releases the hammer which causes discharge

Describe double action in a revolver.

Pulling the trigger causes rotation of the cylinder, cocking of the hammer, and firing of the revolver

How can trigger pull be lightened in single action revolvers?

Altering the rebound slide by cutting spring coils or changing springs to a lighter weight

Polishing the trigger sear

How can trigger pull be lightened in double action revolvers?

Alter the mainspring by changing it out

Polishing the trigger nose/double action sear

Loosening strain screw on leaf type mainspring

what is hammer push off?

The act of the hammer falling when pushed or dropped while in a cocked position without pulling the trigger

How do you fix hammer push off?

Tightening mainspring screw

Replacing hammer/sear/both

what is bullet shearing

When the barrel and cylinder are out of time and not lining up properly, causing fired portions of the bullet to look shaved off

How do you measure barrel length of a revolver?

From the end of the barrel to the inner edge of the barrel (after the cylinder)

What does the direction of cylinder stop notches indicate?

The rotational direction of the cylinder during firing

what is cylinder flare / halo?

Deposits of GSR that collect on the cylinder during firing

What can cylinder flares tell the firearm examiner?

Which cylinder was most recently used

What are the three types of revolver loading mechanisms?

Loading gate cylinder

Swing out cylinder

Pin type/fixed cylinder

What is the primary difference between the old and new model Ruger Blackhawk?

New model has a transfer bar safety

What are six common malfunctions seen in revolvers?

Loose extractor rod

Dirty extractor star

Bullet creep/jump

Short cycling

Broken springs

Out of tune cylinder

Blowback

an unlocked breech that relies on the mass of the breechblock and the strength of the return spring to prevent the breech from opening and the cartridge case from being exposed during its period of peak pressure.

Delayed Blowback

an unlocked breech that has an additional mechanical delay to ensure that the breech bolt doesnt move back before the pressures have dropped enough

Types of Delayed blowback

Roller

Radical

Gas

Lever

What are some advantages of a striker fired system?

Simplicity

Consistent trigger pull

Lightweight

Slimmer profile

What are some disadvantages of a striker fired system?

Lack of second strike capability in most manufacturers

Less crisp trigger feel

What are some advantages of a hammer fired system?

Control over firing mechanism

More crisp trigger pull

What are some disadvantages of a hammer fired system?

Complexity

Bulkier design

What are two things a Jennings Nine has that Jennings 48 does not have?

Magazine disconnect safety

Fixed ejector at 6 o’clock

What are some common observations noted when firing incorrect caliber ammo?

Case bulging/splitting/cracking

Off center FP impression

Pierced primer

Balloting

what is balloting?

when a bullet moves through the bore of a firearm with a bumping, buffeting action, resulting in incomplete/intermittent rifling impressions often extending on the ogive of the bullet.

Ring of fire firearms

Raven

Phoenix

Jennings

Calwestco

Bryco

Jimenez

Sundance

Lorcin

Davis

Cobra

Sedco

Ejection port

An opening in the receiver or slide to allow for ejection of a cartridge, cartridge case, or shotshell.

Feed Ramp

A sloped surface located at the mouth of the chamber that serves to guide the cartridge as it is fed from the magazine into the chamber.

Magazine

A container for cartridges which has a spring and follower to feed cartridges into the chamber of a firearm.

Passive safety

A safety or safety mechanism that is inherent in the design of the firearm and is engaged until operation of the firearm disengages the safety.

Trigger guard

A rigid loop which partially surrounds the trigger to prevent damage or an accidental discharge.

Slide

A component, typically found in semi-automatic pistols, that moves in line with the axis of the bore during the cycle of fire.

What is a pistol?

A handgun in which the chamber is integral with the barrel

Semi-automatic

Firing one round with each pull of the trigger

Fully automatic

Firing continuously as long as the trigger is held down, until ammunition runs out or a malfunction occurs

Trigger pull

The amount of force, in pounds, which must be applied to the trigger of a firearm to cause it to discharge.

Manual safety

Any external, user operated levers or buttons that require deliberate action by the shooter, some typically needing to be disengaged before firing.

Grip safety

An auxiliary locking device on the grip of some handguns which prevents firing until it is fully depressed

How do you know a grip safety is working during a function test?

The trigger either cannot be pulled or does not engage the trigger bar while the grip safety is not fully depressed.

Magazine disconnect safety

A safety device in some semi-automatic handguns that prevents firing unless the magazine is fully inserted into the firearm

How do you know a magazine disconnect safety is working during a function test?

The trigger cannot be pulled or does not interact with the trigger bar when the magazine is not fully inserted

Thumb / manual safety

an external, manual safety that physically blocks the firing mechanism by preventing the sear from releasing the hammer or locking the trigger when engaged.

How do you know a thumb safety is working during a function test?

The trigger cannot be pulled or does not interact with the trigger bar when the safety is engaged

Decocker

Lever or mechanism when depressed that safely lowers the hammer or releases the firing pin from the cocked position.

How do you know a decocker is working during a function test?

when manually pressed the hammer will fall forward without striking the firing pin

Trigger safety

A safety mechanism incorporated into the trigger that, when engaged, prevents rearward movement of the trigger

How do you know a trigger safety is working during a function test?

The trigger cannot move fully rearward without depressing the safety fully

Disconnector

A device intended to disengage the sear from the trigger/trigger bar

How do you know a disconnector is working during a function test?

With the slide slightly out of battery, the trigger is disconnected from the trigger bar and the weapon cannot be dry fired

Cocking indicator

A visual safety that indicates when the firearm is cocked and ready to fire

Loaded chamber indicator

A mechanism that visually shows the firearm has a cartridge loaded in the chamber with a metal tab or pin

Firing pin block

A plunger style safety within a firearm slide that blocks the passage of the firing pin/striker through the firing pin channel

How do you know a firing pin block is working during a function test?

The firing pin/striker cannot be manually pushed forward unless the FP block is simultaneously depressed

What is the cycle of fire for the typical semi-automatic pistol?

Feeding

Chambering

Locking

Firing

Obturation

Unlocking

Extraction

Ejection

Cocking

What does the Colt 1911 Series 80 have that the Series 70 does not?

Firing pin block safety

Cocked and Locked

typically refers to the act of carrying a firearm with a live round in the chamber, a loaded magazine, a cocked hammer, and the thumb safety engaged.

What are the common GRC for a 9mm Luger Hi-Point?

3L

9L

What are the common GRC for a 9mm Luger Ruger?

6R

What are the common GRC for a 9mm Luger Glock?

6R poly

What are the common GRC for a 9mm Luger SCCY?

7R

What are the common GRC for a 9mm Luger Smith & Wesson?

5R

What are the common GRC for a 45 Auto Glock?

8R poly

What are the common GRC for a 45 Auto Colt?

6L

What are the common GRC for a 45 Auto Springfield Armory?

6R

What are the common GRC for a 40 S&W Taurus?

6R

What are the common GRC for a 40 S&W Hi-Point?

7L

What are the common GRC for a 380 Auto Lorcin?

6R

What are the common GRC for a 25 Auto Raven?

6L

What are six common malfunctions that can occur when using a pistol?

Misfire

Hangfire

Failure to feed

Failure to extract

Stovepipe

Squib load

What is a function test?

In the condition received, a dry run examination of the firearm’s mechanical operations is performed without using live ammunition to verify that the safeties and cycling mechanism function without issue