HKPro.com forum poster Marine0303 posted the notes from an armorer’s course he took on the H&K G36 rifle. It is complete with pictures, and provides a really good essential understanding of the design and its maintenance requirements:

As I continue my relentless pursuit towards becoming a HK Master Armorer, I thought I would share another of these Armorer Course posts with you all. I wrote this in a similar fashion as several of my previous posts and hope that you’ll learn something new about the G36. I know I sure did.

One of the first post-Cold War weapons, born out of the fall of the Berlin Wall and the cancellation of the G11 program, the G36 represented a new era in weapons manufacturing from Heckler and Koch. With the amount of money that HK had invested into the unrealized G11 project, the company was in need of significant capital infusions and the German military was still in need of a replacement for their aging G3 rifles. As one of the last of the NATO countries to have not converted to the newer and lighter 5.56mm NATO cartridge, Germany was looking to HK for something cost effective and cutting edge. With the purchase of the company by Royal Ordnance, a massive downsizing and focus on transitioning from the legacy stamped steel, delayed roller locking bolt rifles to polymer construction rifles based on the AR18 system, what evolved in the mid-1990s became known as the G36.

The G36 actually represents what is termed as a “family of weapons”, utilizing a very modular approach to construction, where the receiver is the constant, but a wide variety of stocks, optics/sights, barrels, forearms, feed units and other accessories can be utilized to fill the needs of a specific unit or mission. Extremely successful, since its release, many countries have adopted the G36 as their main service weapon to include Germany, Spain and most recently, Saudi Arabia.

Currently there exist three variants of the G36, the G36 with its 18.8 inch barrel, the G36K with its 12.5 inch barrel and the G36C with its 8.9 inch barrel. There was available for a short time, very recently, a G36 CQB which came with a 15.7 inch barrel as well as MG36 with a heavier full length barrel and bipod, intended to fill the Infantry Automatic Rifle or Light Support Weapon. Though the latter saw testing and limited fielding, including initial evaluation for the US Marine Corps Infantry Automatic Rifle project (which HK later won the contract for with the HK416 submission, now designated M27 IAR), the MG36 was discontinued early into the production of the G36 family of weapons.

All G36 variants are designed to function primarily on the NATO 62 grain 5.56mm full metal jacket cartridge and as such, utilize 1/7” twist barrels for optimal stabilization of that round. Those barrels are both cold hammer forged and chrome-lined, leading to both increased accuracy, initially and over time, as well as increased service life. Additionally, HK cold hammer forges their extractors for the bolt. Generally considered a weak point on weapons utilizing this type of bolt system, not so with the G36. The Director of Training and Technical Services for HK Defense mentioned having never seen or heard of a failure of that specific part.

But the heart of the G36 family of weapons is its self-regulating gas piston (pusher rod) system, which follow what athletes refer to as the Minimum Effective Dose or MED (simply defined as the smallest amount that will produce a desired outcome). In other words, only a small amount of the propellant gas from a fired cartridge is required to cycle the weapon. All excess is vented out the front of the gas block.

Clearly seen in the photo below of a close up shot of the cutaway model of the G36 gas block and piston, the tiny port in the top of the barrel allows a small amount of propellant gas to enter the gas block. That pressure forces the gas piston back against the resistance of the pusher rod and spring, which is then transmitted to the bolt carrier, cycling the weapon for the next shot. The piston only moves a short distance (short stroke), as when its tip passes over the gas port, it presents access to the relief vent and the remainder of the propellant gas is forced forward and vented out that relief vent. As all of the heat or fouling associated with the fired cartridge remains in the area of the gas block and not transferred back within the receiver, like in a direct impingement gas system of operation, the rest of the weapon remains relatively cool and clean, increasing the reliability of the weapon and reducing wear and maintenance needs.

The post is long and contains a lot of really helpful information, and I highly encourage our readers to read the whole thing. He finishes his post with his impressions of the G36:

Overall, I believe the G36 series is one of the most underappreciated of the long guns. An incredibly modular and reliable family of weapons, they require very little maintenance and are suitable for a wide range of missions and environmental conditions. In fact, the main wear items for the guns come down to firing pins and gas piston rings. From an Armorer’s point of view, I also found this weapon incredibly easy to work on, with obvious transitions that were carried over to the weapons that followed like the UMP, MP7 and even HK416.

Of course, many of you are wondering, like I am, if HK is going to offer a civilian version of the G36 like we have seen released in Europe. I asked that question and there is no solid answer. The ability is there, but it would involve some US production that is not currently in place. “So, you’re saying there’s a chance…”