auto gun

This demonstrates the components and cycle of function of the M1911, the iconic pistol designed by John M. Browning for Colt to submit for Army trials in the early 20th century. It remained in main line service for 74 years, is still in use by some branches of the special forces and continues to be extremely popular for competitive, recreational and defensive uses.

Feeding, Chambering, Locking, Firing, Unlocking, Extracting, Ejecting, Cocking.

I was taught to remember it through the ditty “Fat Chicks Like Fucking Unless Eating Easter Candy.”


The recoil spring pushes the action (slide) forward, stripping a round from the magazine, pushing it up the feed ramp and into the chamber, where lugs in the barrel lock into the slide, creating a stable platform for… 


The trigger is pressed, disengaging the sear which releases the hammer to strike the firing pin. The disconnector allows the mechanism to reset without having to release the trigger during the cycle. The slide and barrel travel backward together until the barrel linkage tips the barrel down allowing the locking lugs to clear the slide while…


The rim of the cartridge is held by a notch in the extractor. As the slide travels rearward, the case is carried until it strikes the ejector which propels it up and out of the pistol action. Cocking (demonstrated in the above graphic) occurs as the slide pushes the hammer back, allowing the leaf spring to reset the sear as the hammer is moved to its cocked position.


The grip safety blocks the trigger from moving unless it is compressed while the thumb safety prevents the hammer and sear from moving while engaged. 


Cartridges are basically comprised of a case, bullet, propellant & primer. Cases are typically composed of brass, though steel, aluminum & some advanced polymers are also available.

The firing pin impacts the primer and detonates its pressure sensitive explosive. This ignites the slower burning, but highly expansive propellant. This expansion drives the projectile (bullet) down the barrel & out the muzzle. The case is surrounded and supported by the chamber which contains the pressure of the explosion, preventing the case from deforming.

Cartridges are stacked on top of one another in the magazine and are fed into the pistol action through spring pressure. This particular model is referred to as a single stack. Magazines take on many configurations but detachable single and double stack (staggered) variants are most commonly found in pistols.

Note: Magazines are not clips and clips are not magazines. Clips are small strips of metal that hold cartridges by the rim in order to more easily feed them into a magazine.

anonymous asked:

How does the action on an mg42 work

The MG42 is a recoil operated roller-locked belt fed weapon. 
You have 3 major component groups working in this system:
the fire control group (trigger), the action, and the belt feed mechanism.

The fire control is simple due to the weapon’s open bolt operation. The trigger merely controls a sear that fits into a notch on the bottom of the bolt assembly and keeps it locked to the rear until the trigger is pulled. When the trigger is released, the sear pops back up from spring pressure and stops the bolt on its return stroke. There is no hammer or striker assembly like on other weapons. If you were to draw the bolt back and let it go with the fire control completely removed from the gun, it would fire until it ran out of ammunition or suffered a malfunction. 

The action operates on a recoil operated roller-locking system.
As the bolt assembly moves forward, it strips a round from the belt and moves into locking position as the round is chambered. The wedge shaped striker sleeve then moves forward and forces the two rollers (seen in green below) to cam into position and lock into the barrel extension, which is the squarish part at the chamber end of the barrel.

Because the firing pin is part of the striker sleeve, the gun does not fire until the system is fully locked and safe. After the weapon fires, the bolt and barrel stay locked together and move rearward with recoil. The rollers then cam against the side of the receiver and are unlocked from the barrel extension. After the bolt unlocks, it continues to travel rearward to extract and eject the fired case.  The MG42 also utilizes a distinctive muzzle booster with a cone shaped flash hider. The muzzle booster functions by capturing the expanding gases that result from firing and uses them to apply rearward force on the front of the barrel within the jacket. This  improves reliability of the system as the force from both the recoil and the expanding gases are used to unlock the system and apply rearward force on the bolt.

This smooth roller system and fast lock time is what resulted in the MG42′s  infamously fast fire rate of fire of ~ 1,200 rpm.

The belt feed mechanism of the MG42 was a very influential design due to its simplicity and reliability. The top cover of the feed mechanism houses a swinging cam track that interfaces with a raised cam on the top of the bolt body. 

 As the bolt travels forward and back, the cam causes the track to swing back and forth, which works the feed pawl that pulls the belt through the system and line up ammunition for feeding.

This .gif from shows the operation of the M60 machine gun, which took heavy influence from the MG42. The feed mechanism functions identically.

I hope that clears things up for you, and you have somewhat of an idea of how the MG42 works. I’m not the best at writing really.