The Thompson submachinegunGun Library ArticleBlowback


What do you know about the blowback operating system and the firearms that used it?

Each firearm has its own firing mechanism, with advantages and disadvantages. The history of firearms includes not only the maturation of the American firearms, but also the development of the additional equipment, ammunition and firearm operating systems. From all the operating systems invented throughout the time, the blowback operation has remained as one of the most innovative and highly effective. Found in both semi-automatic and fully-automatic firearms, the blowback operating system functions using as a source of energy from the chamber combustion.

As there are various types of blowback systems, it is to be understood that there are just as many or even more firearms under those categories. The simple blowback operating system can be usually observed in the world renowned Uzi submachine gun; then there are the roller-delayed, gas-delayed, lever-delayed, toggle-delayed and chamber-ring delayed operating systems. All of these will be carefully discussed in the following lines, highlighting the basic principles and also the advantages. In addition, there are the hesitation locked blowback systems, encountered in the 51 pistol from Remington and the blish lock, commonly found in the first Thompson submachine guns (today no longer in use).

There is no knowing for certain who patented the blowback operating system but he certainly would have been famous. This particular firearm action was intended for weapons that utilize low pressure rounds and from what we have seen so far, the best blowback operating system can be observed in semi-automatic pistols firing small-caliber ammunition and also in automatic submachine guns. The blowback operating system was also implemented in certain grenade launchers, but the success was not as incredible as it was expected.

The introduction of the delayed blowback operating systems managed to revolutionize in certain ways the firearms manufacturing industry, allowing for more potent rounds to be used.

The roller-delayed was observed in rifles, submachine guns and also pistols, manufacturers being proud of a system that was both simple to use and at the same time incredibly effective. Soon, the lever-delayed mechanism was introduced, using the power of a lever to postpone the opening of the breech. The mechanism was first implemented in Hungary but it was quickly adopted by a lot of countries, including America. They started to use it for creating submachine guns and also powerful carbines.

When the gas-delayed blowback operating system was first introduced on the market, many people were uncertain of what the difference between this particular system and the gas-operated system really was. Things were made clear when everyone observed the gas-delayed mechanism to use propellant gases for the pushing of the bolt. German manufacturers produced rifles and pistols using that operating system, increasing their popularity worldwide. Still, there were many more discoveries to be made in the field of firearms action and time was going to prove that.

It was a man named John Pedersen that patented a new operating system, called the hesitation locked.

That mechanism used for the first time a separate breech block, causing at the firing of the cartridge the bolt and the slide to move together. The energy came from the cartridge, just as in other similar blowback systems. Though the patented system was considered to be groundbreaking, history records only one single pistol to have been manufactured using the hesitation locked system, meaning the 51 Remington. There were many other famous blowback operating systems, including the one made by the famous ‘Carbine’ Williams. He concentrated on developing a system that allowed firearms to fire 22 rim-fire caliber ammunitions and he succeeded. The mechanism was patented and interpreted as the accelerated blowback system. John Garand was also known for developing a blowback system, called primer actuated. However, it took a long period of time for the system to be accepted.

As for blowback systems that are no longer in use, the blish lock was a complete innovation in its time. It was a breech locking mechanism, designed by John Bell Blish and was especially used in Thompson submachine guns. Also, John Savage tried his luck hoping to revolutionize firearm actions, with the Savage rotating barrel system. After many years, it was discovered that the so called mechanism was just the basic blowback operating system.

The 51 Remington model has remained in the history of American firearms as being the only one pistol to ever use the hesitation locked patented system.

The small pocket pistol was brought to existence by the same John Pedersen and was produced under the famous Remington name at the start of the 20th century. From 1918 and several years to come, the 51 Remington enjoyed immense popularity, Remington Arms manufacturing an incredible number of 65000 units, suitable for both 32 ACP and 380 ACP calibers. The pistol had advanced features, including an internal hammer and a single-action trigger. The breech block was separate within the slide, increasing the efficiency of the weapon. The gun was going to remain widely known and extremely appreciated, not only for being the only pistol to use Pederson’s patented system but also for the superior quality and innovative features included.

And if we are going to talk about the 51 Remington and the hesitation locked mechanism, it would be a shame not to say a few words about the man who made it all possible. John Pederson was an important name for the American firearms manufacturing industry, designing a wide variety of firearms for Remington Arms. He worked side-by-side with John Browning, another illustrious gun designer and together they’ve came up with the notable 17 Remington model. Pedersen was a man longing to invent revolutionizing devices and he managed to accomplish most of his dreams. He is the inventor of the Pedersen device, which allowed the conversion of the 1903 rifle into an auto-loading weapon, adapted for medium-size calibers. In the years to come, Pedersen worked for the American Army and constantly competed with John Garand, another famous inventor.

No matter what John Pedersen did, the Remington 51 model remained widely appreciated for its qualities. The grip safety was innovative, being both comfortable and easy to use. Pedersen was a man that occupied his time with the smallest details, wanting his inventions to achieve the highest degree of perfection. His gun was sold as small pocket pistol and was especially welcomed by civilians. If at the start the gun was not so well received, in a short period of time its popularity reached sky limits. Among the famous men who owned a Remington 51, there was General S. Patton, who put all his confidence into this weapon and praised it extremely. In modern years, there are many companies that have tried to adopt the patented Pederson system, including the Italian firm Bennelli. As far as the original model is concerned, there are both advantages and disadvantages to its use. It is easy to operate but it has one major disadvantage, the complexity of the trigger and safety mechanisms.

Some experts have declared that the 51 Remington was not so well received because it was ahead of its time. And in many aspects, they were right as it took another couple of years for similar firearms to appear on the market, under different names and also with different expectations.