Shouldering the AK

By Lucas Bernard

With the AR, there aren’t really many options when it comes to stocks. Essentially, you have the option of a fixed stock or a collapsing stock. Yes, there are different types available for both, but they are more or less variations upon a theme. One of the few weaknesses of the AR is that the operating system extends past the rear of the receiver, so all AR stocks have to be built around the receiver extension.

On the other hand, the AK’s operating system is completely contained within the receiver and barrel assembly. The stock does not have to be built around anything. Nowadays, most people have stamped receiver AKM derivatives. With AKM stocks, everything begins with the rear trunnion. It is a piece of forged metal riveted into the rear of the receiver that the stock is mounted to. One negative is that changing your stock to a different type may require changing out this component, which is something that requires a professional AK builder. In essence, there are four main types of rear trunnions for AKM’s. 

  1. The fixed stock trunnion – Consisting of a tang sticking rearward out of the receiver, it is primarily designed to accept a fixed stock. Robust and simple, they are typically made of laminated wood, have a trap door for a cleaning kit, and a sling swivel. It is important to note that regular AKM fixed stocks have a shorter length of pull than what Americans are accustomed to, as they were anticipated to be used with heavy winter coats. While perfect for small statured people like this author, non-hobbits may be interested in the “NATO” sized polymer AK fixed stocks. Now like anything else with AK’s, a little filing and sanding may be required. More modern designs, like those from MAGPUL, have adjustable wedges that don’t require such labor. Along with fixed stocks, this trunnion can accommodate a certain type of folding stock, colloquially known as the “wire” or “crutch” type. Various former socialist countries made stocks of this type, such as Romania, Poland, and Egypt. These fold towards the right, not interfering with a side rail optics mount. The American market has also brought forth adapters that will fit AR receiver extensions, so one can use their preferred adjustable AR stocks. 
  1. The underfolder stock trunnion – Taking design cues from the MP40, the AKMS is seen around the world. Being designed for paratroopers and tankers, while not being able to accommodate a left side optics rail, the stock can clear a standard 30-round magazine with ease, and the rifle can be fired folded or unfolded. It features a left side sling swivel that is positioned where the receiver meets the stock, where modern shooters are used to. When folded, it is easily hidden away, and equally easy to turn into a full sized rifle at the press of a button and the flick of the wrist. This utility made it a regular tool of Marxist guerrillas throughout the Cold War. If your AK was built with a fixed stock trunnion, switching over to an underfolder is no easy task. Underfolder trunnions require specialized cuts in the receiver to fit the stock assembly. If you wish to have an underfolder, it is best to buy or have one built from the outset. 
  1. The side folder trunnion – First introduced in the AK74 series of rifles, it was a classic of the Soviet-Afghan war. In its original incarnation, it utilized a triangular stamped steel stock that folded to the left side of the rifle. In more modern times, the AK-74M utilizes essentially a folding version of the fixed stock. Some consider this the best of both worlds. Like all other AK folders, it can be fired folded or unfolded. It can accommodate a left side optics rail, although it can’t be completely folded with the optic attached. Changing a fixed stock AK into a side folding AK is easier than an underfolder, but will still require a skilled builder to do correctly.
  1. The pistol trunnion – This style is an invention of the American market. It essentially just plugs the rear of the receiver. Typically installed on AK “pistols”, these are designed to meet the needs of American regulatory realities. Much like stock Glock sights, they are placeholders. Once the gun is turned into an SBR, it is replaced with a regular trunnion. 

Which type of stock is best? That depends on your needs and personal tastes. The fixed stock trunnion is the most versatile, the underfolder the most compact, and the side folder a healthy mix of both. Just make sure you have a good quality AK to start with, especially if you plan on switching out the rear trunnion. 

From the FE Films Archive

See More Films from Field Ethos

You May Also Like