Topic 8 - Muzzle Attachments Flashcards
What is the flat end of the barrel called?
The crown
What can crown damage cause?
Markings
- Potentially deflect the bullet’s path.
- Anomalous markings and scratches on the bullet with potential forensic significance.
What is the noise we here when a firearm goes up caused by?
|Pressure wave, supersonic, mechanical
- Pressure wave from rapidly expanding gases going supersonic.
- Supersonic crack if the bullet goes supersonic.
- Mechanical action noise of the firearm itself
- Any other flight-related noises e.g. air friction
What is pressure wave caused by?
Ignition of propellant
The pressure wave is caused by the rapidly expanding gases produced from ignition of the propellant inside the ammunition cartridge case becoming supersonic as they leave the muzzle.
What sound component can be reduced with a sound suppressor?
The supersonic pressure wave is generally the only sound component from the firearm that can be reduced by using a sound suppressor.
What do sound suppressors do?
They reduced the sound produced by supersonic gases
Why are sound suppressors ineffective?
- There are other sources of sound
- Supersonic bullets create their own “sonic boom”
When can suppressors be useful? (ammunition)
Subsonic ammunition
What are the legal restrictions on sound suppressors?
Legally, they are prohibited unless specified on a firearms certificate for a particular weapon.
How do sound suppressors work?
Slowing, expansion, turbulence, controlled chamber
- Sound suppressors function by slowing the gases leaving the muzzle.
- This is achieved by allowing expansion of the gases and applying turbulence to the gas flow within a controlled chamber (the suppressor) to slow down the gases to below the speed of sound upon release to the external environment.
What are basic components of a sound suppressor?
- Expansion chamber
- Baffles
What are the different types of sound suppressors?
- Can
- Baffle
- Reflex
- Active
What is a can suppressor?
A hollow can-shaped extension on the muzzle: not very effective.
What is a baffle?
A can with partitions for the pressure wave to impact and transfer energy to (losing velocity).
What is a reflex?
Internal complexity
A can with baffles and additional internal complexity, providing expansion chambers behind the baffles for the pressure wave to impact and transfer more energy to.
What is an active sound suppressor?
spring-loaded
A reflex suppressor with spring-loaded baffles which further transfers the energy away from the pressure wave.
Where should a sound suppressor be mounted?
Concentric to the bore axis
What happens if the sound suppressor is mounted wrong?
The suppressor can shatter
How are suppressors checked to ensure they’re safe?
Suppressors must be proof tested and may be certified safe for the ammunition that they are designed to be used with.
What are the different types of recoil reducers?
Compensators
- “Muzzle brakes” - external accessories & the most effective.
- “Recoil compensators” - integral to the firearm & less effective.
How do recoil reducers work?
Redirecting, muzzle brake, rearwards
- They work by redirecting propellant gases to counter the recoil of the firearm.
- Combustion gases will typically leave the muzzle brake at an angle pointing in a rearwards direction, acting like a thruster on an aircraft to pull the weapon in the opposite direction to the recoil forces.
When is recoil the highest and lowest?
Recoil is usually greatest for large-caliber slow moving projectiles and is less for fast small-caliber projectiles
What do typical forms of recoil reducers include?
Tube
- A short length of tube attached at 90o to the end of the barrel, diverting the gases sideways to counteract the gases normally pushing the barrel
upwards. - Laser-cut slots in the muzzle end of the barrel (Magna porting).
What are the drawbacks of recoil reducers?
Gas blast
- Recoil reducers will increase the noise of the firearm and the gas blast is directed back towards the firer.
- They could also give away covert positions by disturbing debris on the ground.