Annex A Flashcards
Weight of auto gun receiver
90lbs
Weight of barrel assembly (ribbed)
107lbs
Weight of barrel assembly (non-ribbed)
95lbs
Weight of automatic gun feeder
59lbs
Weight of total gun system (ribbed)
256lbs
Weight of total gun system (non-ribbed)
244lbs
What is time to rate
0.15 sec the time from when the gun receives the signal to start until mechanical actions begin to start
What is time to stop
0.12 sec the time from when the gun receives the signal to stop until mechanical actions begin to stop
What two types of internal finishes does the ribbed barrel have
Nitride and chrome
What internal finishing is required for the enhanced gun
Chrome
What are the features of the enhanced receiver
Larger breech assembly, longer recoil, triple spring drive clutch and a BIT ready gun drive motor
What are the features of the enhanced feeder
Quick detachable link covers and a BIT ready feed select solenoid
What are the components of the forward feed section
Forward feed assembly, Upper feed sprocket assembly, lower feed sprocket assembly, round positioner assembly, feeder assembly rotor, ejection chute
What strips HE rounds from the links and places them in the feeder assembly
Lower feed sprocket assembly
What is the purpose of the round positioner assembly
Guides and positions the rounds during transfer from the sprocket assembly to the feeder assembly rotor
Sub assemblies of the receiver assembly
Barrel support assembly, Recoil Mechanism, Breech assembly, Sear, Sear catch assembly, Sear retractor assembly, mechanical interlock, Direct Current motor, Handle Pin, Electrical Sear solenoid, Riveted Reciever
What are the components of the electrical system
1.0 Horse Power 24 VDC motor, Sear solenoid, electrical feed select solenoid and index drive cable assembly
The interlock crank, Rocker assembly, and Sear Pushrod, are components of what
Mechanical Interlock
What is the peak recoil force of the M242
9,000lbs Enhanced 12,000 Standard
As the bolt completes the ram cycle what happens
The cam indent reaches the roller on the breech lock sensor arm
List the steps in the cycle of operation in order
Sear, Feed, Ram, Lock, Fire, Unlock, Extract, Eject
The 2 ring spring set is part of what component
Recoil Mechanism
In a malfunctioning weapon how much of the gun stopping power does the Sear assemble provide
100%
What is the primary function of Sear
To positively position the roller assembly chain master link at the end of the firing burst, thereby orienting the gun components for feed selection
What occurs during feed dwell
The master link slider moves from left to right in the carrier slider path during the feeder assembly rotor will rotate 1/3 of a revolution during this rotation the rotor will sweep the spent case off the bolt face positioning a new round on the bolt face the firing pin is not cocked and the BPI arrow is rotating through feed/ do not remove feeder
How much overlap is there to prevent a new round from being fed into the breech
12.7mm normally 2.5 in the event of a failed cartridge ridge
For the M242 to continue to function, normal gun functioning must occur within what amount of time
30 miliseconds
In a malfunctioning weapon the Sear assembly provides 100% of the guns stopping power by stopping what
The Roller assembly chain safety link
As the bolt assembly continues forward for the last 14.2mm of travel what happens
The firing pin spring is compressed
What is the last measurement of movement of the firing pin as the firing pin spring is compressed
14.2mm
When is the bolt at its most rearward position
Feed dwell
How far rearward is the bolt from Sear when it is in feed dwell
25mm
What are the purposes of the muzzle brake
Countering some explosive recoil force, Disperses muzzle blast and reduces blast flash
How much recoil is needed to deactivate the rocker assembly
12mm minimum, 14mm Typical, 18mm Maximum
What do continuous rim guide and the positive T slot extractors ensure throughout the entire gun cycle
Continuous control of the round position
What two things occur once the normal shutdown sensor has been activated
Power is withdrawn completely from the electrical Sear solenoid and power is also shunted from the 1.0 HP VDC motor
What failure modes have been identified which represent all modes where the gun WILL CONTINUE TO FUNCTION WITHOUT HANGFIRE PROTECTION
Push rod extension or externally relieved screw breaks. Bolt carrier cam pin breaks. Sear assembly breaks. Interlock crank breaks. Electrical Sear solenoid intermittent
The micro switches are joined together by what
The micro switch sensor harness assembly
What occurs during fire dwell
Slider moves from right to left in the carrier slider path allowing time for the hot propellant gases escape and chamber pressure to return to safe level prior to unlocking the bolt bpi arrow is rotating through fire poly is making its final locking position
How much force does the firing pin spring deliver to the primer
32 inch pounds
How much coverage do the t slot extractors provide
30 degrees on top 75 on bottom 105 degrees of over all coverage
What does the 1.0 Hp VDC drive motor assembly provide
Ammunition feeding, loading and firing, extraction, and ejection
What is the second purpose of the Sear
To locate receiver components for proper time of the feed and receiver during assembly
Approximately how much recoil is absorbed by the recoil mechanism
Approximately 85%
How far back can the link slingers move a long round
9.5mm
What voltage range does the M242 electrical system operate on
18-28VDC
What are the components of the MSIS
Rocker Assembly, Operating Rod Assembly, Interlock Crank, Push rod extension, Sear Pushrod
What does the electrical system consist of
1.0 HP 24 VDC motor, Electrical Sear Solenoid, Electrical feed Select Solenoid, Index drive cable assembly
What two components ensure continuous control of the round positioner Through the entire gun cycle
Positive t slot extractors and rim guide
In a normally functioning gun what activated the gun shutdown sequence
Normal shutdown sensor
As the bolt completes the ram cycle, the cam indent reaches the roller and activates and deactivates what microswitch
Breech lock sensor
What is the M242 power transmission system comprised of
1.0 HP 24 VDC motor, feeder drive assembly, chain and bolt drive
Dynamic breaking in a normally functioning gun accounts for how much of the guns stopping power
80-85%
The recoil mechanism is comprised of what
Two ring spring set and hydronic damper
Ammunition feeding, loading and firing, extraction, and ejection are all done by what component
1.0HP 24 VDC motor
In a malfunctioning gun what provides 100% of the gun stopping power
sear assembly
The microswitches that are joined together by the microswitch harness assembly are arranged around what component
Control cam
What is the desperation of rounds for the M242
.5mil (1m diameter at 1000m)
How much stopping power does the Sear assembly account for in a normally functioning gun
15-20%
How far can the link aligners move short and long rounds
Long 9.5mm back short 3.1mm forward
When is the firing pin compressed
As the bolt assembly continues forward for the last 14.2mm of its travel
What collects, processes and sends appropriate signals to the traverse drive assembly the elevation actuator and control display assembly
Gun turret drive electronics
When in fine lay the turret moves how many mils each full rotation
10 mils
When in course lay the turret moves how far with each full rotation
60 mils
What does the upper drive assembly providing the final traverse drive gear engage
442 gear teeth
What does the Arm/Safe switch do
Controls arming and sanding of the weapon system
When does the low ammo indicator illuminate
37 rounds for AP 31 rounds for HE and 100 for Coax
The ELRF/DVO is equipped with what magnification direct view optic
8X
What does TMI do
Updates the thermal system to denote movement in the scene
STARE is best used when
The vehicle is stationary traversing or elevating the turret will cause video smearing to be seen in the display
Who must have a fundamental understanding of the procedures and theory involved with the operation of the LAV-25A2 turret equipment in order to effectively utilize the equipment
Cremen
Describe weapon power circuit breaker
Applies power to the weapon and vent blower
What is the description of the range button
When depressed will electronically activate the ELRF and update the ballistics solution
What adjusts the position of the ballistic sight reticle to allow zeroing of the sight and weapon system
Deflection and elevation knobs
When faults are active the STAB AZ indicator light and the STAB EL indicator light will make a series of flashes and form a two digit what
Fault code
How do you null drift when the STAB AZ and EL indicators do not flash a fault sequence
Depress the palm switch for 10 seconds without any Hand Control deflection
What is located between the gunner and commander provides turret crew with controls and annunciators for the fire control system
Control diasplay assembly
When does the low battery indicator flash
When the voltage has fallen below 19.5 volts
What does the Grenade launcher group consist of
3 switches and one indicator light
What fire control modes does the reticle switch have
Normal and stadia
How does the CDA identify a fault condition
By flashing the temperature/ Fault indicator
When set to LACE how does the system operate
In a
