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Phone: 612.412.1448

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Lilja 6mm ARC Barrel

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We're thrilled to announce a partnership between Six Sigma Arms, LLC and Lilja Precision Rifle Barrels to bring a phenomenal new offering to the the market in 6mm ARC.

These barrels are currently being offered in multiple profiles/lengths; 12.5", 16", AR24/22.5", and AR740/19.5". Barrels are all threaded 5/8-24. There is not currently an option for re-profiling and/or fluting of the barrel. Schematics of the profiles are available for the 12.5", 16", AR24, AR319, and AR740 barrels.

Any/all machine work is performed in-house by Lilja (including chambering, extension install, threading, etc). Barrels are chambered using SAMMI specs. These barrels are threaded for and furnished with a pinned barrel extension installed with proper headspace. The gas port hole is drilled and these are finished off with an 11° target crown. A narrow flat on the bottom side of the gas port section is milled for set screws used with some types of gas blocks. This prevents marring of the diameter by the set screws and helps align the gas block with the gas port hole. Barrels use an M4 style barrel extension and are ready to drop in to your selected upper. As with all Lilja barrels, these have 3-groove rifling and a 1:7" twist. Both barrels utilize a rifle length gas system (12"). Barrel markings will be in front of the gas block. Markings read, "Lilja 6ARC 1-7 Six Sigma" ("Lilja" will be in their customary script font).

Finish from Lilja is polished stainless steel, finish ground to 320 grit. Optionally, we can Cerakote these prior to final delivery for an additional $75 in a number of colors (black, desert, FDE, tactical grey, etc). Cerakote will add a few weeks to delivery time. If you select Cerakote, we will reach out to you to discuss the details.

We also have 6mm bolts that we source directly from Lilja that work in perfect harmony with these barrels. If you add a bolt to your order, it will be headspaced to your barrel and coded accordingly.

Shipping is included in the price. If you would like a complete custom upper, please Contact Us and we can work out a quote.

A quick note about barrel lengths; the measurements noted above are measured from the muzzle to a closed bolt (standard ATF measurement). The overall length of the barrel will measure approximately 1/2" longer.

Price: $455 $430

In Stock


If you have questions or can't find what you're looking for please contact us via our website or email us at sales@sixsigmaarms.com. We have access to significantly more items than what we have listed on our website.

Note: Items marked "In Stock" are on site at one of our facilities and ready to ship immediately unless the item notes indicate otherwise. Items marked "Available" are available through one of our distribution channels and will be acquired as soon as possible to fulfill your order. Select items are available for "Backorder" as well. These items will be ordered (or already have been ordered) and will be fulfilled as soon as they are received. Payment is due at the time of your order. For special arrangements, please feel free to give us a call. Thank you!