OSA Pin & Weld Muzzle Device Service

Need to make your 13.7", 13.9", or 14.5" AR-15 barrel compliant with the federal 16" minimum rifle barrel length? Our Pin & Weld Service permanently attaches your muzzle device to the barrel using accepted permanent-attachment methods, allowing you to enjoy the handling benefits of a shorter barrel while meeting applicable federal barrel-length requirements.

Every installation is performed with careful attention to alignment, proper torque, timing, and long-term durability to ensure a clean and professional finished product.

What's Included

• Professional muzzle device installation

• Proper timing and torque of the muzzle device

• Precision drilling for pin installation

• Hardened steel pin installation

• Permanent weld over the pin

• Clean finished appearance

• Final inspection of the completed installation

Optional Existing Pin & Weld Removal

Already have a pinned and welded muzzle device that needs to be removed before installing your new muzzle device?

Select Existing Pin & Weld Removal when placing your order.

This option is intended for barrels that already have a permanently attached muzzle device and require removal of the existing device before OSA can install and pin/weld the replacement.

The service includes:

• Identification of the existing pin and weld location

• Careful removal of the existing weld

• Removal of the retaining pin where possible

• Removal of the existing muzzle device

• Inspection of the barrel threads and muzzle area

• Preparation for installation of the new muzzle device

• Installation and pin & weld of the new customer-supplied muzzle device as part of the primary service

Important Information About Pin & Weld Removal

Removing a previously pinned and welded muzzle device requires machining through or around the existing weld and pin. Because previous pin-and-weld work can vary considerably between manufacturers and gunsmiths, OSA cannot guarantee that the existing muzzle device will be reusable after removal.

The primary goal of this service is to preserve the barrel and its threads whenever reasonably possible, not to preserve the muzzle device being removed.

In some cases, the existing muzzle device may need to be cut, drilled, machined, or otherwise permanently damaged in order to safely remove it.

If excessive previous welding, damaged threads, an improperly installed pin, or another issue is discovered, OSA will contact you before performing work outside the scope of the selected service.

If your barrel already has a pinned and welded muzzle device, this option must be selected when placing your order.

Parts Required

Please include the following components with your order:

• Barrel

• Barrel Nut

• Gas Block

• New Muzzle Device

• Existing pinned/welded muzzle device, if already installed

Important: Your barrel nut and gas block must be installed before the new muzzle device is permanently attached. If your barrel nut is specific to your handguard, be sure to include it with your shipment.

Our Thoughts

A proper pin and weld is more than simply welding a muzzle device onto a barrel.

The muzzle device must first be correctly timed and torqued, ensuring ports, compensators, or suppressor mounts are properly positioned. Once correctly installed, the muzzle device and barrel are prepared for a hardened steel pin that mechanically secures the device before the weld permanently covers the pin.

The result is a secure, permanent attachment with a clean, professional appearance.

Plan Your Build First

Because the muzzle device becomes permanently attached, there are several important considerations before sending your barrel in.

Once the pin and weld is complete:

• The barrel nut generally cannot be removed over the muzzle device.

• Many gas blocks cannot be removed over the muzzle device.

• Changing handguards may require removal of the pinned and welded muzzle device.

• Replacing the gas block may require removal of the existing muzzle device.

For that reason, we strongly recommend deciding on your rail, barrel nut, gas block, and muzzle device before having the service performed.

It's also an excellent time to install a quality gas block—and, if desired, have it pinned before the muzzle device is permanently installed.

Compatibility

This service is commonly used for:

• 13.7" barrels

• 13.9" barrels

• 14.5" barrels

• Other barrel lengths where permanent muzzle-device attachment is being used to meet applicable minimum barrel-length requirements

The selected muzzle device must provide sufficient length when permanently attached for the completed barrel assembly to meet the applicable legal requirement.

Not every muzzle device will bring every short barrel to the required length.

If you're unsure whether your barrel and muzzle device combination is compatible, contact Ocean State Armory before placing your order.

Pricing Information

The listed base service price applies to:

• Stripped barrels

• Complete upper receivers with an accessible muzzle device

Removal of an existing pinned and welded muzzle device is not included in the standard Pin & Weld Service price and must be selected as an additional option when ordering.

The service does not include unrelated upper receiver assembly, disassembly, parts replacement, or repair unless specifically selected or approved beforehand.

Important Information

• Customer is responsible for providing a compatible muzzle device unless otherwise arranged with OSA.

• Existing pin-and-weld removal does not guarantee preservation of the old muzzle device.

• Previously damaged barrel threads or improperly performed pin-and-weld work may require additional service.

• Additional work will not be performed without customer approval.

• Permanent attachment should be considered permanent and may require machining to reverse in the future.

• It is the customer's responsibility to ensure the completed firearm complies with all applicable federal, state, and local laws.

Final Verdict

A professionally performed pin and weld allows you to build around the balance and handling characteristics of a shorter barrel while using a permanently attached muzzle device where appropriate.

And if your barrel already has a pinned and welded muzzle device, OSA can handle the process from removing the existing device through installing and permanently attaching the replacement.

Every project is completed with careful attention to fitment, alignment, machining, and finished appearance.

Whether you're building a lightweight carbine, suppressor host, competition setup, or duty-style rifle, the OSA Pin & Weld Muzzle Device Service provides a clean and professional permanent-attachment solution.