3p0x1b CDC Vol 2 (2016)

The lower receiver and buttstock assembly houses various components such as the trigger assembly, sear, hammer assembly, selector lever, rifle grip, bolt catch, and buttstock assembly. These components are essential for the functioning of the firearm. The lower receiver is the main housing for the trigger group and other important parts, while the buttstock assembly provides support and stability for the shooter. Therefore, the lower receiver and buttstock assembly is the correct answer.

The M249 AR has a fixed type of headspace. This means that the distance between the face of the bolt and the base of the cartridge is predetermined and cannot be adjusted. This fixed headspace ensures consistent and reliable ignition of the cartridge, contributing to the overall reliability and accuracy of the firearm.

The correct answer is Cartridge, 5.56mm, ball, M855. This is the standard round used in the M16A2 and M4 series weapons, as well as linked and used in the M249. The M855 ball round is a 5.56mm NATO cartridge that is commonly used by the United States military. It is designed for general-purpose use and has a full metal jacket with a lead core. The M855 round provides good accuracy and penetration, making it suitable for a variety of combat situations.

During the cycle of operation of the M9 pistol, the feeding stage occurs as the slide moves forward and a round is stripped from the top of the magazine. This means that the slide is bringing the next round into position to be chambered and fired. This stage is crucial for the pistol to function properly and for the shooter to be able to fire subsequent rounds.

To prevent a short recoil malfunction caused by improper gap space in the gas rings, the bolt rings should be staggered approximately 1/3 turn apart. This means that each ring should be rotated about one-third of a full turn from the adjacent ring. By staggering the rings in this manner, it helps to ensure a more secure and effective seal, reducing the chances of gas leakage and malfunction during recoil.

The correct answer is M200 Blank. The M249 round of ammo is distinguished by its seven petal rosette crimp and violet tip, which matches the characteristics of the M200 Blank ammunition. The other options, M232 Dummy, M196 Tracer, and M193 Ball, do not have the same crimp or tip color, making them incorrect choices.

The serial number on a shotgun is located on the receiver. The receiver is the main part of the firearm that houses the firing mechanism and connects the barrel, stock, and other components. It is typically made of metal and is where the serial number is engraved or stamped. This is done for identification and tracking purposes, as the receiver is considered the controlled part of the firearm. The stock, barrel, and magazine may also have their own markings or identification numbers, but the serial number is specifically located on the receiver.

The correct answer is "Host nation requirements." This means that personnel may use hollow point ammo if it is allowed by the requirements of the host nation. This could include any regulations or laws set forth by the country in which the personnel are operating. It is important to adhere to these requirements to ensure compliance with the laws of the host nation.

When inspecting the barrel assembly of the M240B machine gun, it is important to check for any bulges, bends, burrs, obstructions, or pits in the chamber or bore. The chamber is where the cartridge is loaded and fired, so any issues with it can affect the gun's performance and safety. The bore refers to the inside of the barrel, and any irregularities in it can impact the accuracy and effectiveness of the weapon. Therefore, it is crucial to thoroughly examine these areas to ensure the proper functioning of the M240B machine gun.

The most likely malfunction in this scenario is that the locking block and lugs are cracked, burred, or broken. This would prevent the slide of the M9 pistol from fully locking forward. The locking block and lugs are crucial components that ensure the proper functioning of the slide, so any damage or breakage in these parts would cause the malfunction described.

The correct answer is "cocking handle assembly". The explanation is that the cocking handle assembly is the part of the M249 AR that moves on a guide rail fixed to the right side of the receiver and pulls moving parts rearward. This action allows for the chambering of a new round and prepares the weapon for firing.

The Mossberg 12 Gauge model 590 shotgun has a cylinder choke. A cylinder choke is a type of choke that has no constriction, meaning it does not narrow or constrict the shot pattern. This type of choke is ideal for close range shooting, as it allows for a wide and even spread of shot.

Turning the MK19 machine gun windage screw counterclockwise adjusts the horizontal alignment of the sight. This means that it moves the sight to the left, allowing for more accuracy when aiming to the left of the target.

The correct answer is 1500 meters. The rear sight range plate of the MK19 machine gun is incremented in 100-meter intervals from 300 to 1500 meters.

During the firing cycle of operations for the MK19 machine gun, when the trigger is pressed, the trigger depresses the operating rod. The operating rod, in turn, depresses the tip of the receiver sear. The receiver sear is responsible for holding the firing pin in place. When the receiver sear is depressed, it releases the firing pin, allowing it to strike the cartridge rim and initiate the firing sequence. Therefore, the correct answer is receiver sear.

The correct answer is if the cover is completely down and latched. This is because if the cover is not completely down and latched, it may result in a malfunction while feeding ammunition. The cover acts as a protective barrier for the ammunition and ensures proper functioning of the M2 machine gun.

If the GO end of the headspace gauge enters freely all the way to the ring, it indicates that the headspace of the M2 machine gun is within the acceptable range. The fact that the NO GO end does not enter further suggests that the headspace is not too loose or too tight. Therefore, the headspace is correct.

The maximum range for the M240B machine gun is 3725 meters.

The MK19 machine gun can provide base defense units with automatic HE (High Explosive) fire support up to a distance of 2212 meters. This means that it is capable of engaging targets and providing support at a range of 2212 meters or less.

This 12 gauge breaching cartridge is specifically designed to gain access through light doors and entry ways. It may not be powerful enough to breach steel reinforced doors or heavy armored vehicles, but it is suitable for lighter materials commonly found in entry ways.

The carriage and cradle assembly is responsible for providing a mounting platform for machine guns and ammunition brackets in the MK64 gun cradle. This assembly is designed to securely hold the machine guns and ammunition brackets in place, allowing for easy access and operation. It ensures that the guns and ammunition are properly positioned and stable during use, enhancing the overall functionality and effectiveness of the MK64 gun cradle.

The Mossberg 590 shotgun is different from the Mossberg 500 because it has a detachable heat shield. This feature allows the shooter to quickly remove the heat shield if desired. The Mossberg 500, on the other hand, does not have a detachable heat shield. This difference in the heat shield feature sets the two models apart from each other.

Insufficient gas pressure can be a primary cause for a failure to feed in the M240B machine gun. This is because the gun relies on gas pressure to cycle the action, which in turn feeds the next round into the chamber. If there is not enough gas pressure, the action may not cycle properly, resulting in a failure to feed. This can occur due to various reasons such as a malfunctioning gas system, a clogged gas port, or insufficient gas being generated by the ammunition.

The M918 Target Practice (TP) is the correct answer because it is stated that this round contains a pyrotechnic charge that emits a flash bang signature upon impact. This feature allows the round to simulate the service ammo, making it suitable for training and practice purposes. The other options do not mention any pyrotechnic charge or flash bang signature, indicating that they do not possess the same simulation capabilities as the M918 TP.

The correct answer is a round of ammo not fully seated in the barrel. This means that the bullet has not been properly loaded into the chamber of the barrel, causing a malfunction. This can happen if the round is not inserted correctly or if there is an issue with the feeding mechanism. It is important to ensure that each round is properly seated in the barrel to prevent malfunctions and ensure the firearm functions correctly.

During the feeding cycle of operation for the M240B machine gun, the actuating rollers move the feed lever side to side. This movement of the feed lever causes the feed pawls to also move. The feed pawls are responsible for stripping a round from the belt of ammunition and positioning it correctly for loading into the weapon's chamber. Therefore, the correct answer is that the actuating rollers moving the feed lever side to side moves the feed pawls.

The M397 HE Jump up fragmentation round is designed to inflict personal casualties using an air-burst effect. This means that when the round is fired, it explodes in the air above the target, causing fragmentation to rain down and potentially harm or kill individuals in the vicinity. This type of round is often used in military operations to engage enemy personnel and disrupt their movements.

A bird scare cartridge is a 12 gauge shotgun cartridge that contains a pyrotechnic projectile. This projectile is housed in a corrugated plastic case with a brass plated steel base. Bird scare cartridges are commonly used to scare birds away from crops or other areas where they may cause damage. The pyrotechnic projectile creates a loud noise and bright flash upon impact, effectively frightening the birds and causing them to disperse.

The firing pin block is the part of the M9 pistol that sits between the firing pin striker and the firing pin. It is designed to prevent the firing pin from moving forward and striking the primer of a cartridge unless the trigger is pulled. This safety feature helps to prevent accidental discharges and ensures that the firearm can only be fired when intended.

The correct answer is 5 inches because the free length of the M9 Pistol recoil spring should not be less than this measurement. This length is necessary to ensure proper functioning and reliability of the pistol. A shorter recoil spring could result in insufficient energy absorption and could potentially cause malfunctions or failures in the firearm's operation. Therefore, it is important to adhere to the recommended minimum length of 5 inches for the recoil spring.

The M203 barrel assembly is specifically designed to chamber and launch low velocity 40mm grenade launcher ammunition. This type of ammunition is used for shorter range engagements and is typically employed for close quarters combat or when firing from within a confined space. The low velocity ammunition allows for better control and accuracy in these situations, making it the appropriate choice for the M203 barrel assembly.

The M232 Dummy round of ammo is the correct answer because it is specifically designed to simulate the weight and dimensions of live ammunition, but it does not contain any propellant or primer. This makes it safe for training and practice purposes, as it does not produce a projectile or any explosive force when fired.

The correct answer is the disassembly button. In weapons nomenclature, the disassembly button is typically located on the right side of the receiver, above and ahead of the trigger guard. This button is used to disassemble the weapon for cleaning, maintenance, or repair purposes. The magazine release button, extractor button, and slide stop button are all different components of a firearm, but they are not located in the same position as described in the question.

To ensure a seal is created when replacing the bolt carrier key, it is recommended to fire 3 to 8 rounds of blank or ball ammunition. Firing this number of rounds helps to properly seat the key and create a tight seal, ensuring optimal performance and preventing gas leakage.

Incorrectly positioning the first round of a partial belt on the M249 AR feed tray can cause a failure to feed/strip malfunction. This means that the weapon will not properly feed or strip the next round from the belt, resulting in a failure to fire. This can lead to sluggish operation and a failure to chamber the next round, ultimately impacting the overall functionality of the weapon.

The bolt and operation rod assembly is responsible for providing feeding, stripping, chambering, firing, extraction, and ejection of cartridges in the M240B machine gun. This assembly uses the projectile propelling gas for power to perform these functions.

The correct answer is 25 meters or less. This means that if there are not enough range facilities for sustainment training, short range training ammo (SRTA) can be used for any firing exercise within a distance of 25 meters or less. This allows for training to still take place even without access to longer range facilities.

Performing a function check is the first thing you should do when you have an unknown malfunction and your MK19 machine gun won't shoot. This involves going through a step-by-step process to check all the functions of the weapon and identify any specific problems that may be causing the malfunction. By performing a function check, you can systematically troubleshoot and locate the issue before taking any further action such as clearing the weapon or turning it in for maintenance.

The M2 machine gun operates on the short recoil principle. This means that when the gun is fired, the force of the recoil pushes the barrel and bolt assembly rearward. As the barrel and bolt assembly move back, the bolt unlocks from the barrel and continues to move rearward, extracting and ejecting the spent cartridge case. The recoil spring then pushes the bolt forward, chambering a new round and locking it into place. This principle allows for rapid and continuous firing of the weapon.

The tripod head is the part of the M3 Machine gun tripod that provides a front support for the weapon. It is responsible for holding the weapon securely in place and allowing it to be rotated horizontally. The tripod head is designed to provide stability and balance to the weapon, ensuring accurate and controlled firing. It is an essential component of the tripod system, allowing the gunner to effectively engage targets in different directions.

During the M249 AR cycle of operations, extracting begins during unlocking. This refers to the phase when the bolt carrier group moves to the rear, unlocking the bolt from the barrel extension. As the bolt moves back, it extracts the spent casing from the chamber and prepares for the ejection process. This is a crucial step in the firing sequence as it ensures the removal of the fired round before the next round is chambered and fired.

The correct answer is 1 inch. This means that if cracks found on the M203 handguard assembly during preventive maintenance checks and service (PMCS) exceed 1 inch in length, it would render the assembly not fully capable. Cracks exceeding this length may compromise the structural integrity and functionality of the handguard assembly, potentially affecting its performance and reliability.

The M973 Short Range training Ammo is used for training in local and urban areas where range restrictions prevent the use of full range standard service ammo. This suggests that the M973 round is specifically designed for shorter range training purposes and is likely to have reduced range capabilities compared to other rounds.

The correct answer is 10 1/16 in. 25.56 cm minimum to 11 1/4 in 28.58 max. This is the correct range for the free length of the action spring on the M4 Carbine. The action spring is an important component that helps to cycle the weapon and ensure proper chambering of rounds. By inspecting the action spring within this specified range, any potential failure to chamber malfunction can be identified and addressed.

The M240B machine gun ammunition feeds from a bandoleer that holds 100 rounds of ammunition. This means that the bandoleer is designed to carry and supply the gun with 100 rounds of ammunition, ensuring that the gunner has an adequate amount of ammunition readily available for use.

The M16A1 gauge kit is used to test for barrel erosion on the M2 machine gun. This gauge kit is specifically designed for the M2 machine gun and allows for accurate measurement of barrel erosion. It is important to regularly test for barrel erosion as it can affect the performance and accuracy of the weapon. The M16A1 gauge kit ensures that the barrel is in good condition and can help identify any necessary maintenance or replacement needs.

The correct sequence when performing the firing pin protrusion test on the M203 grenade launcher is to first cock the launcher, then move the barrel forward, followed by removing the self-locking screw, and finally squeezing the trigger. This sequence ensures that the firing pin protrusion is tested accurately and safely.

The Bore constriction check tool is used to detect detents and minor damage in the M203 that would interfere with forward progress of fired projectile.

Firing blank ammo at a target less than 20 feet away is unsafe. Blank ammunition still contains gunpowder and can cause injury or harm if fired at close range. The distance helps to ensure that the force and impact of the blank round is reduced, minimizing the risk of injury to the shooter or others nearby. Therefore, it is important to maintain a minimum distance of 20 feet when using blank ammunition for safety reasons.

The train and elevation assembly is the correct answer because it provides both travel lock and mechanical fire control adjustment capability in one unit. This means that it allows the machine gun to be securely locked in place during travel and also allows for precise adjustments in the gun's aim and firing mechanism. The other options, such as the multipurpose bracket assembly, universal pintle latch assembly, and machine gun mount assembly, do not offer both of these capabilities in one unit.