Sons of Liberty Broadsword M89

Why 6mm ARC on an AR-15 Platform

6mm ARC (Advanced Rifle Cartridge) was designed specifically to extend the effective range of an AR-15-pattern rifle well past what 5.56 NATO can manage, while still cycling through standard AR-15 magazines and bolt carrier groups with only a barrel and bolt change. It shoots flatter and retains more energy at distance than 5.56, making it a popular choice for shooters who want more reach without moving to a larger-frame rifle like an AR-10.

The Broadsword M-Lok Handguard System

The Broadsword M89 takes its name from SOLGW's Broadsword handguard, a free-floating M-Lok rail system built to the same over-built standard as the rest of the SOLGW lineup. The rail's attachment to the upper receiver is reinforced beyond a typical AR-15 handguard interface, reducing flex under a bipod or forward grip during precision shooting positions.

Barrel Length Options: 14.5" Pinned, 16", and SBR

The Broadsword M89 is available with a 14.5-inch pinned barrel (pinned and welded to reach 16 inches of legal overall barrel length without NFA registration), a standard 16-inch barrel, and a true short-barreled rifle configuration for buyers who complete NFA registration. The pinned 14.5-inch option is a popular way to get a shorter, more maneuverable barrel profile without the SBR paperwork and wait time.

Who the Broadsword M89 Is For

The Broadsword M89 fits shooters who already run an AR-15 platform and want to extend their effective range for hunting or long-range shooting without adopting a larger, heavier .308-class rifle. It's not the right choice for someone who just wants a standard 5.56 range rifle — for that, SOLGW's Scalper is the more straightforward and more affordable option.

Frequently Asked Questions

What is 6mm ARC and why choose it over 5.56?
6mm ARC is a cartridge designed to shoot flatter and retain more energy at distance than 5.56 NATO, while still cycling through standard AR-15 magazines and bolt carriers with just a barrel and bolt change.

Is the Broadsword M89 SBR legal to buy without NFA paperwork?
No — the SBR configuration is a short-barreled rifle and requires ATF Form 1 or Form 4 registration. The 14.5" pinned-barrel version reaches 16" overall length without needing SBR registration.

Can I use standard AR-15 magazines with the Broadsword M89?
Yes — 6mm ARC was designed to run in standard AR-15 magazines alongside 5.56 loads.

Should I get the Scalper or the Broadsword M89?
The Scalper is SOLGW's standard 5.56 NATO rifle for general-purpose use. The Broadsword M89 is a dedicated 6mm ARC platform for shooters specifically extending their long-range capability.

Browse our full 6mm ARC Ammo selection and see Sons of Liberty Gun Works for the brand's full lineup.