Pakistan Army Trials and the Resurgence of the Roller-Delayed Blowback

In 2016, Pakistan started one of the most extensive weapon trials in modern history. The country was planning to replace millions of G3 rifles and AKs used by military and paramilitary forces, find the best modern battle rifle, and acquire its manufacturing technology from the OEM.

For the winner of the trials, the future procurement contract was estimated at well over one billion USD. The contenders included FN SCAR, CZ Bren 2, Beretta ARX-200, MPT-76 from Turkey, PWS from the US, and Zastava M77 from Serbia.

Each manufacturer sent a team of representatives and shooters to make sure the rifles would perform to their fullest potential. For over six months, rifles were tested in every imaginable environment, from the hellish heat of the deserts of Sindh province to the freezing temperatures of the mountain peaks in the north of the country.

For weeks, these rifles shot accuracy tests at 100, 400, and 600 meters using locally made ammunition. Pakistan Ordnance Factory personnel measured the recoil, the flash, dropped guns from different heights, and froze rifles in portable fridges to -50°C (-58°F).

At some point, rifles were disassembled, their parts were mixed, and the guns were reassembled and checked with gauges to ensure complete interchangeability of parts.

Simultaneously, various units in the Pakistan army tested the same rifles. Their methods were less precise but nevertheless effective: bury the weapon underground, throw the weapon in the mud pit filled with water, simulate a sandstorm - commanders had complete freedom to develop their own testing procedures.

The last stage of the trials required each team to shoot 10,000 rounds with each of three rifles. A total of 30,000 rounds for every manufacturer. Every day, each rifle shot 1,200 rounds in full auto, and every morning, rifles were tested for degradation of accuracy, increase in headspace, and other critical parameters.

The author of this article participated in all the stages of trials, and it was definitely an unforgettable experience. And while most aspects of those trials are still classified, there was one finding that was quite unexpected.

Along with all those foreign rifles, the army also tested the old Pakistani-made G3. And to everyone’s surprise, the old German rifle did very well in most tests, especially in terms of accuracy and reliability.

You know what they say: “An old horse won't spoil the furrow, but won't plough a new one either”. You can’t just expect the rifle designed in the 1950s to be an adequate weapon in the 2020s. But you also can’t ignore the fact that the G3 is a capable rifle, even compared to modern counterparts.

Engineers of Pakistan Ordnance Factory found a compromise: they developed a new rifle based on G3’s roller delayed action, but with modern features.

The better-known variant is called BW20; it resembles the G3 and is made on the same manufacturing equipment. I already talked about it in my articles. There are several versions of it: “Assaulter” with the short barrel, Designated Marksman Rifle (DMR), and CW39 chambered for 7.62x39.

But there was one more prototype called BW21, which is essentially a rolled-delayed blowback action put in the AR-10 style rifle. It was developed much earlier, in 2010; however, the prototype was only produced in 2019 after trials confirmed that rolled-delayed blowback is by no means outdated. Recently, the designer of this rifle, Salman Ali, uploaded to his channel the following video about the history of this rifle in English.

In the video, he explains the main motivation behind this project, quote: “I have a keen liking for roller-delayed blowback system, and I just feel like it is too good a system to be lost in history, and it holds a lot of potential. So I want to do all I can so the roller-delayed blowback mechanism keeps going forward”.

By design, the roller-delayed blowback system has certain advantages - with it, you can have a true free-floating barrel, since there is no gas system connected to the barrel.