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Module 8: Examination of Firearms - Coggle Diagram
Module 8: Examination of Firearms
Cycle of Fire Steps
Feeding
Chambering
Locking
Firing
Obturation
Unlocking
Extraction
Ejection
2 more items...
the act of withdrawing a cartridge (or cartridge case) from the chamber of a firearm; frequently performed in conjunction with unlocking
the reverse of the locking process; frequently performed in conjunction with extraction
the sealing of gases due to the expansion of a cartridge case as a result of chamber pressure
when the breech is fully locked, a pull on the trigger mechanically translates to the firing in release
the manual or automatic locking or supporting of the bolt of a firearm immediately prior to firing
the reaming out of a chamber in the end of a barrel blank or cylinder; the act of inserting a cartridge in the chamber
refers to the insertion of cartridges into the chamber, where the breech bolt pushes the cartridge into final position
Evidence & Examination Documentation
when a firearm examiner receives a piece of evidence, it should be accompanied by documentation and any requested examinations
the sequence of examinations is important and should be determined before any examination is started
examination worksheets should be completed with each completed examination, which will guide the examiner
Firearms Identification Information
any firearm produced or imported to the US is required to have identifying information
brand name
trademark
model designation
caliber designation
importer
military firearms often do not have caliber designations, but rather codes and symbols used by the manufacturers; measuring the bore diameter and chamber can provide the examiner with the information needed
examiners may need to rely on proof marks for older, foreign firearms, which may be found in reference books
handguns
revolvers - handguns with a multi-chambered cylinder
single action
double action
pistols - handguns with a chamber that is an integral part of the barrel
semiautomatic
fully automatic
single- and multibarreled
long (shoulder) firearms
rifles
four types of magazines
removable box
internal box
rotary
tubular
incorporate several action types
bolt
pump/slide
autoloading
lever
falling block
rolling block
shotguns
single barrel
break open
pump/slide
bolt
semiautomatic
double barrel
also caliber shotguns have choke that controls the pellet pattern spread
full (most restriction)
modified (some restriction
cylinder (no restriction
Safety Features of Firearms
the NRA has three fundamental safety rules anyone handling a firearm should abide by
always keep a firearm pointed in a safe direction, away from other people
always keep your finger off the trigger until ready to shoot
always keep a firearm unloaded until ready to use
Test Firing
function
bullet recovery
additional testing
Drop Test
a test used when prior examination finds no evidence for an accidental discharge
Safety in the Laboratory
be aware of any and all safety procedures
be responsible for your own safety and that of others in the lab
handle every firearm as if it were loaded until ensuring it is unloaded