Threading Barrels for Suppressors: Legalities & Performance Tips

Whether you’re a hunter looking to protect your hearing, a competitive shooter managing recoil, or simply a firearms enthusiast interested in suppressors, threading your barrel is a smart — and increasingly popular — upgrade. But it’s not just a matter of cutting threads and screwing something on.

At Redleg Guns, we offer precision barrel threading services for shooters who demand performance, safety, and legal compliance. Here’s what you need to know before modifying your rifle or AR-platform firearm for suppressor use.

🔧 What Does “Threading a Barrel” Mean?

Threading a barrel means machining external threads at the muzzle end so a device — such as a suppressor, muzzle brake, or flash hider — can be securely attached.

It may sound simple, but quality threading must:

• Be perfectly concentric to the bore (to prevent baffle strikes in suppressors)

• Match the correct thread pitch and diameter for your device

• Maintain the integrity and accuracy of the barrel

That’s where precision machining from an experienced gunsmith comes in.

🤫 Why Add a Suppressor?

Suppressors (aka “silencers”) offer several advantages:

• Hearing protection — less noise exposure for shooter & bystanders

• Reduced recoil & muzzle rise — improves follow-up shots

• Less environmental disruption — great for hunters

• Better communication — ideal for team-based or tactical shooting

In short, they make shooting more comfortable, safer, and more accurate — especially with properly matched and installed equipment.

📏 Common Thread Sizes for Suppressors

Thread specifications depend on caliber and platform. Here are some common ones we deal with at Redleg:

Caliber	Typical Thread Size
.223 / 5.56	1/2x28
.308 / 7.62	5/8x24
9mm	1/2x28 or 13.5x1mm LH
.22LR	1/2x28
.338	3/4 24 or 5/8x24

Note: These must be exactly concentric to the bore — not just the barrel exterior. Poor threading can result in baffle strikes or suppressor damage.

⚖️ Is It Legal to Add a Suppressor in Minnesota?

Yes — suppressors are legal in Minnesota, but there’s a process.

Here’s what you need:

• Be 21 or older

• Be legally able to own a firearm

• Submit a Form 4 (NFA application) with a $200 tax stamp

• Pass a background check and fingerprinting

• Wait for ATF approval

Once approved, you can take possession and use the suppressor legally — and Redleg can help ensure your firearm is properly threaded and suppressor-ready.

👉 You do not need the suppressor in hand to thread the barrel — but we do recommend knowing the exact make and model before machining.

🧰 Why Professional Threading Matters

If your barrel is even slightly out of alignment, your suppressor could be damaged — or worse, you could experience a catastrophic baffle strike.

At Redleg Guns, we:

• Use precision lathes and dial-indicators to ensure concentricity to the bore, not just the barrel exterior

• Verify thread pitch and muzzle finish for tight suppressor lock-up

• Test and inspect the crown for any accuracy-impacting imperfections

We also offer thread protectors, timing shims, and muzzle devices if you're not running a suppressor full time.

🔩 Minimum Barrel Diameters for Threading — and Why It Matters

Not every barrel is thick enough to be safely threaded — and choosing the right thread size for your caliber is only part of the equation. For example, a 1/2x28 thread (common for .223/5.56) requires a minimum barrel diameter of about 0.500" at the muzzle, while a 5/8x24 thread (typical for .30 cal like .308/6.5 Creedmoor) needs about 0.650". If the barrel is too thin, threading can weaken structural integrity or prevent proper shoulder alignment, risking baffle strikes or device loosening. At Redleg, we always measure your barrel’s diameter first and, if needed, recommend alternatives like rebarreling, thread adapters (where appropriate), or changing thread pitch — all to ensure safety, performance, and longevity.

🛠️ What If the Barrel Is Too Thin for a Proper Shoulder?

When a barrel doesn’t have enough diameter to provide a solid shoulder for the muzzle device to seat against, threading it without modification can cause serious issues. A weak or absent shoulder can allow the suppressor or brake to “walk up” the threads, pushing it out of concentricity — and that’s a recipe for a baffle strike or poor accuracy.

At Redleg Guns, we solve this by doubling the length of the threads and threading on a precisely machined collar or extension with a larger outside diameter. This custom piece creates a proper shoulder for the muzzle device to torque against, preserving alignment and maintaining safety. It’s one of those behind-the-scenes steps that separates a precision build from a risky shortcut — and it’s standard practice in our shop when needed.

🔄 What If My Barrel Isn’t Long Enough?

If your barrel is too short to safely thread, we may recommend:

• Barrel replacement

• Pin & weld of a muzzle device to achieve legal overall length

• Thread adapters (though these aren’t ideal for suppressor use)

  
  

Let us take a look — we’ll advise the best, safest path forward based on your goals.

👋 Final Thoughts: Suppressor-Ready the Right Way

Threading your barrel opens the door to suppressors, brakes, comps, and other muzzle devices — but it’s not a DIY job for the average shooter. Precision, legality, and safety are critical.

📍 Located in southwest Minnesota, Redleg Guns offers expert barrel threading and suppressor-ready services for bolt guns, ARs, and more.

Whether you're gearing up for your first suppressor or modernizing your hunting rig, we’re here to help — from threading to build consulting to custom barrels.

📞 Ready to Thread Your Barrel?

✅ Contact us to schedule a threading service📞 Call: (507) 677-6007📧 Email: info@redlegguns.com