Threading Barrels for Suppressors: Legalities & Performance Tips
Updated: 3 days ago
Threading a muzzle is not hard. Threading it concentric to the bore is, and that is the only part that matters. Threads cut true to the outside of the barrel instead of to the bore will look perfect and still walk a suppressor off axis, and the way you find out is a baffle strike. The specs are straightforward: 1/2x28 for .223 and 5.56, 5/8x24 for .30 caliber, and the barrel needs roughly 0.500 inch of diameter at the muzzle for the first and 0.650 inch for the second. If your barrel is thinner than that, the answer is not a smaller thread, it is a threaded collar that gives the device a real shoulder to torque against.
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.
When it comes to threading barrels for suppressors, precision and alignment matter far more than most shooters realize.
At Redleg Company, 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.
Most threading jobs look good.
Very few are actually concentric to the bore.
What Does Threading Barrels for Suppressors 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.
If you have not bought the can yet, start here. The process changed in 2026 and the sequence matters:
Why Add a Suppressor?
Suppressors (aka “silencers”) offer several advantages:
This is why threading barrels for suppressors has become one of the most requested upgrades we see in the shop.
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:
When threading barrels for suppressors, minimum diameter and proper shoulder support are critical for safety and performance.
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.
The technical side of this, concentricity, shoulder geometry and what actually causes a strike, has its own article:
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) as of January 1, 2026, the $200 tax stamp has been eliminated. The process, background check, and registration requirement remain in place, but the financial barrier is gone.
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.
Transfers, out of state purchases and what Minnesota requires are covered separately:
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 Company, 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.
Mastering Extreme Accuracy in Gunsmithing: A Detailed Approach to Precision Chambering Rifle Barrels
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 Company, 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.
One thing nobody warns an AR shooter about: a can changes the gas system, and the rifle will tell you about it in the face:
What Threading Does Not Fix
A suppressor is not an accuracy upgrade, and threading is not a tune-up.
A can will usually shift your point of impact and it will often tighten groups slightly by damping muzzle blast, but it cannot correct a rifle that was not shooting straight before. If your groups were open before the threading, they will be open after. The rifle deserves a diagnosis, not a muzzle device.
And if the barrel is worn rather than untuned, adding weight to the muzzle changes nothing about that either:
What it looks like when we settle that question properly, on a real rifle:
The honest caveat: we thread a lot of barrels and most of them come off rifles that shoot fine. This section is not a reason to skip threading. It is a reason not to expect it to solve a problem it was never aimed at.
Frequently Asked Questions
Do I need to thread my barrel to use a suppressor?
Yes, unless the barrel already came threaded or you are using a device that mounts another way. The threads are what hold the can concentric and secure, and they have to be machined for it.
What happens if barrel threads are not concentric to the bore?
The suppressor sits at a slight angle to the bullet's path. At the muzzle the error is invisible. By the time the bullet reaches the last baffle it can be far enough off center to clip it. That is a baffle strike, and it destroys the can and sometimes the barrel.
What is the most common thread size for suppressors?
1/2x28 for .223 and 5.56, and 5/8x24 for .30 caliber including .308 and 6.5 Creedmoor. The right one for your rifle depends on caliber, barrel diameter and the device, not on what is common.
Can any barrel be threaded for a suppressor?
No. There has to be enough steel at the muzzle to carry the threads and still leave a solid shoulder. Roughly 0.500 inch of diameter for 1/2x28 and 0.650 inch for 5/8x24. Thinner than that and threading weakens the barrel or leaves no shoulder for the device to seat against.
What do you do if my barrel is too thin to thread?
We double the thread length and fit a precisely machined collar with a larger outside diameter, which gives the device a proper shoulder to torque against. It is standard practice in our shop when the barrel calls for it, and it is the difference between a safe job and one that lets the can walk up the threads and go out of alignment.
Do I need the suppressor in hand before threading?
No, but you should know the exact make and model. Mounting systems vary, and the thread and shoulder we cut should match the device you are actually going to run.
Is it legal to own a suppressor in Minnesota?
Yes. You need to be 21 or older, legally able to own a firearm, and you have to complete the ATF Form 4 process including a background check and fingerprints, then wait for approval. As of January 1, 2026 the $200 tax stamp no longer applies, but the registration and approval process is unchanged.
Can I thread my own barrel?
We would not. This is a lathe operation where the reference has to be the bore, not the outside of the barrel, and getting that right needs the barrel dialed in on an indicator. A threading die run over the muzzle by hand follows the barrel's exterior, which is exactly the error that causes strikes.
What if my barrel is too short to thread legally?
Options are a barrel replacement, or pinning and welding a muzzle device to reach legal overall length. Thread adapters exist but they add a joint and a tolerance stack, which is the last thing you want between a bullet and a baffle.
Will a suppressor change my point of impact?
Almost always, and usually by more than shooters expect. Plan to re zero with the can on, and understand that taking it off moves the zero back. If you hunt with it on, zero with it on.
Will threading hurt my accuracy?
Not if the crown is respected. The crown is what controls how gas leaves the muzzle behind the bullet, and a threading job that damages or ignores it will cost accuracy. We inspect and, where needed, recut the crown as part of the work.
How long does barrel threading take at Redleg?
Call the shop at 507-677-6007 for current lead time. It is a bench operation rather than a build, so it moves faster than a barrel job, but the shop is booked out and the honest answer changes by the week.
Do I need a thread protector?
If you are not running the device full time, yes. Exposed muzzle threads get dinged, and a damaged thread is either a recut or a new muzzle. A protector is a few dollars against that.
Does a suppressor make my AR run dirty?
It increases back pressure, which sends more gas and carbon into the receiver and into your face. It is a real effect and it is fixable with an adjustable gas block and the right buffer, but it is worth knowing before you shoot a hundred rounds through a suppressed AR.
What does Redleg charge to thread a barrel?
Call 507-677-6007 or see the services and pricing page for the current figure. Tell us the caliber, the barrel's muzzle diameter and the suppressor you plan to run, and we can tell you on the phone whether your barrel supports it.
Final Thoughts: Threading Barrels for Suppressors - 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 Company 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.
Book the Work
Redleg Company threads barrels for bolt guns and AR platforms out of Chandler, Minnesota, and rifles ship to us from across the country. Call 507-677-6007, or read the standard and the pricing on the services and pricing page. Tell us the caliber, the muzzle diameter and the device and we can usually answer on the phone.
Redleg Company, 430 Main Avenue, Chandler, Minnesota. Phone 507-677-6007. Email info@redlegguns.com.
Suppressor hunting in Minnesota, and which rifle to put the can on:
And the action work that decides whether the rifle was worth threading in the first place:
Reloaders: our free reloading sheets are here.
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