What is a Nielsen Device?

Nielsen Devices, also known as muzzle boosters, exist to help short recoil guns cycle properly and overcome the excessive weight at the end of the barrel. Because the barrel has to move in such a system, the weight of a silencer often requires extra force to help cycle the gun.

Getting suppressed handguns to reliably cycle with a wide range of ammunition has long been a problem. Issues with gas pressure and even the weight of the suppressor have all conspired to jam a great many suppressed handguns. The most common solution to this is a recoil booster or Nielsen Device. This ensures sufficient energy is available to cycle the handgun, even when using subsonic ammo. But what is a Nielsen Device, and how do recoil boosters work? Let’s take a look.

Using Recoil Boosters for Suppressed Handguns

Semi-auto pistols work by transferring energy from a fired round in such a way as to cycle the action. This can be through simple backward pressure of the fired round, or as complex as tapping gas to work a piston. Various ways of locking and unlocking slides exist. In the simplest form, spring pressure holds the slide safely closed until the force of a fired round overcomes the spring pressure and cycles the slide. These blowback actions are very simple, but also do not suppress well because of the nature of their operating system.

Short recoil systems found in most handguns also require the energy of the fired round to operate and require the barrel to move some short distance as well. This is where we start running into problems, as the added weight of the suppressor usually is enough to prevent the gun from properly cycling. That means we need to “boost” the pressure at the muzzle to help make up for the added weight of the suppressor, and sometimes the lower pressure of subsonic rounds.

Enter the Nielsen Device, also known as a muzzle booster.

How Does a Nielsen Device Work?

Muzzle boosters exist to help short recoil guns cycle properly and overcome the excessive weight at the end of the barrel. Because the barrel has to move in such a system, the weight of a silencer often requires extra force to help cycle the gun.

Muzzle boosters retain some of the gas exiting the muzzle long enough for it to push back against the barrel and add additional backward force to ensure the barrel travels as far back as it is supposed to. Some machine guns required this due to the weight of their barrels, while suppressed handguns may require it in order to make up for the weight of the silencer itself on the gun, or even to work better with lower pressure subsonic ammo.

Every bullet leaving the barrel of a gun has a blast of gas coming right behind it. A Nielsen device works to momentarily contain and direct some of that gas backward. Think of it as a sort of reverse muzzle brake. A muzzle booster traps and holds gas long enough to direct it backward and then bleed off. Because silencers also trap and hold gas, it’s simple to adapt them to include a Nielsen device.

Muzzle boosters are also referred to as pistons, and many popular handgun suppressors are designed to work with pistons that their suppressor mounts on.

Do I Need a Muzzle Booster?

Well… maybe. There is no hard and fast answer. If you are running a straight blowback gun like a .22 or a Walther PPK like James Bond (Or Sterling Archer…) then you don’t need one.

But what about on a short recoil-operated handgun, such as basically every handgun more potent than a .380 and even a great number of smaller calibers?

Then pretty much yes, you do need or want a piston. It’s possible that some gun/ammo/suppressor combos could work without a piston, but you really need one for reliability. Typically, a handgun suppressor ships with a piston. Also common is the ability to buy a muzzle booster apart from the silencer because often pistol silencers are used on multiple guns and calibers.

Choosing a Muzzle Booster

This is crazy simple really. Buy a handgun silencer. Silencers like the all-titanium, multi-caliber BANISH 45 are available with several different sized pistons so you can use them on different guns. We also sell extra pistons for common calibers and thread pitches.

In fact, all major handgun suppressor manufacturers make multiple pistons available or build their silencers around common piston patterns and sizes. Just check when you are shopping for a suppressor which pistons fit and what’s available.

In fact, there is usually no real reason to shop muzzle boosters, except to ensure the correct fit with your silencer and barrel. They all do about the same thing about the same way and achieve the same purpose. So just stick with the ones your silencer manufacturer recommends (or builds).

When NOT to use a Nielsen Device

There are lots of times you shouldn’t use a muzzle booster. These include direct blowback guns, single-shot pistols, most AR/AK or similar pistols built around rifle style actions, bolt action pistols, and of course rifles.

The whole purpose of a muzzle booster is to deal with the added weight of a silencer on the barrel of a short recoil-operated firearm. Some of the smallest AK style pistols may benefit from one as well, but such notable exceptions are both rare and well documented to a given style of gun.

As a general rule, if the barrel isn’t fixed to the frame, you probably need a muzzle booster, and if it is fixed to the frame, you don’t need a muzzle booster.

Ready to Buy A Silencer?

Or just have more questions? No problem! Drop us an email or call us and we’ll be happy to help you select the perfect silencer and muzzle booster for your handgun. As the nation’s largest silencer dealer, we sell more silencers to more people than anyone else. Licensed in all 42 silencer-legal states, we’ve got the perfect silencer for your needs!

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