Muzzle thread cutting? All info from BAER

If you're not a police officer or don't spend your free time at a shooting range, chances are you've never held a firearm in your life. Especially when compared to the USA, firearms don't play a significant role in Germany. However, that doesn't mean there aren't any guns in the country. Nearly 950,000 private individuals were registered in the National Firearms Register in 2022, owning a total of over five million firearms or firearm parts. Sounds pretty significant, doesn't it?

In such a volatile topic, precise craftsmanship is crucial, as it concerns safety. Of course, precisely cut threads are a part of this. And since precise threads are our passion, today we're discussing threads on firearms. Or to be more precise, a particular thread at the muzzle of a firearm. Not only does it have an exciting function, but its manufacturing process is also intriguing. So, let's talk about the muzzle thread!

What is a muzzle thread?

The muzzle thread has a single purpose: it facilitates the attachment of a silencer to the barrel of a weapon. If you're suspecting shady dealings at this point, perhaps you've watched too many crime dramas. There are legitimate reasons for using a muzzle signature reducer, as it's termed in official jargon. A quiet shot offers advantages not just for hitmen but also for hunters. At the same time, the silencer reduces recoil and even enhances accuracy.

However, for it to function, it needs to be attached to the barrel, which is where the muzzle thread comes into play. Thanks to this thread at the weapon's muzzle, the silencer can be easily screwed on, ensuring a secure attachment. For this to work reliably, the muzzle thread must have the right dimensions and meet some strict standards.

What are the dimensions of a muzzle thread?

The term muzzle thread does not refer to a specific thread standard. Any thread at the muzzle of a firearm is a muzzle thread, irrespective of its exact size. Nevertheless, its size isn't irrelevant. The diameter of the muzzle thread must be adjusted to the barrel thickness to prevent the wall of the barrel from becoming too thin. Metric fine threads are suitable because they offer greater self-locking than metric regular threads. This provides an extra layer of safety when connecting the barrel and silencer. In Europe, the metric ISO fine thread is commonly used as the muzzle thread. For a standard hunting rifle, M 14 x 1 is used, with larger barrels employing M 15 x 1 or M 16 x 1.

Also, you should always have the appropriate nut on hand. If you decide to remove the silencer, it's essential to protect the delicate muzzle thread from damage and contamination, ensuring its precision remains intact. The easiest way to do this is by screwing a nut onto the muzzle thread.

Cutting a muzzle thread – Not a task for amateurs

Usually, we encourage you to cut threads yourself, be creative, and experiment. However, in the case of the muzzle thread, you should absolutely avoid doing this. In fact, it's legally prohibited, unless you happen to have a firearm manufacturing license. If that were the case, you'd probably already know everything about muzzle threads and wouldn't have read this far.

So, creating a muzzle thread is solely the job of a gunsmith – which is why it's sometimes referred to as a gunsmith thread. And that's a good thing because cutting muzzle threads requires expertise. A minor oversight can have fatal consequences. Gunsmiths, like Peterssen Gunworks, will handle your firearm and precisely cut a reliable muzzle thread into the barrel, ensuring you can safely rely on it afterwards. Any modification to your firearm must then be approved again by the firearms authority. This process might take time, but it ensures no nasty surprises later on.

How the muzzle thread is produced

The most critical and first step in producing a muzzle thread is ensuring the correct alignment of the thread. Otherwise, the bullet might touch the baffles inside the silencer. The gunsmith doesn't rely on the barrel's outer profile but on the so-called axis of the bore. This is an imaginary axis that runs right through the middle of the barrel, from which the bullet exits. Determining the exact bore axis and cutting the muzzle thread in precise alignment requires not just extensive experience but also the right equipment.

Once the gunsmith has determined the correct alignment of the muzzle thread, the actual cutting process begins. First, they clamp the barrel into a lathe, and if necessary, trim it to the desired length. A live center ensures precise alignment throughout the process. The muzzle thread is pre-cut to half its depth on the lathe, after which the muzzle is chamfered. The final thread cutting is done with a thread cutting die.

Throughout and after the production, clean and meticulous work is paramount. The muzzle thread is repeatedly polished and checked for burrs or chips to eliminate any disturbances. Finally, the quality of the muzzle thread can be verified by screwing on the corresponding nut. Your firearm is now ready for discreet operation!

While you shouldn't cut muzzle threads yourself, there are plenty of other fun projects to tackle! And all the thread and assembly tools you'll need are available in BAER's online store, a tap manufacturer. Browse at your leisure, and if any questions arise, our customer service is here to assist. We look forward to serving you!