When I began my outdoor writing career around 2006, every rifle I tested seemed to have some type of AR variant. Most of them are excellent weapons, but it would be hard to say anything new and unique about rifles other than that. Innovation is subtle and incremental at best.
This year I finally get the chance to talk about a new and unique AR rifle. Ruger’s new Small Frame Automatic Loading Rifle (SFAR) does something no other rifle I know of has done: it is chambered in .308 Winchester but essentially in a .223-sized package.
Let’s go back to the 50s, where this story begins. When Armalite’s Eugene Stoner invented the AR rifle we know today, he made it in 7.62×51. This rifle, commonly known as the AR-10, was later scaled down by Stoner and Jim Sullivan to become the 5.56×45 AR-15 that was later developed.
Although functionally similar, AR-10s are larger and heavier than AR-15s (an average of two pounds heavier), making them less suitable for widespread use. Over the years, many users have pursued the power of the AR-10 without regard for its weight and volume, leading ballisticians to effectively exploit the performance available in smaller caliber rifles.
The result was the development of specialized cartridges such as the 6.5 Grendel and 6mm ARC. For the SFAR, Ruger engineers took a completely different approach. They found a way to use the AR-10 – .308 Win cartridge. – Clips efficiently onto AR-15 size rifles. The result is a combination of .308 performance, versatility and ammunition availability in a lightweight package.
Visually, the SFAR basically looks like an AR-15 with an AR-10-sized magazine. The SFAR currently comes in two models: the Model 5611, a full-size rifle with a 20-inch barrel, and the Model 5610, a carbine with a 16.10-inch barrel. They weigh 6.8 pounds and 7.3 pounds respectively. I tried the more compact 5610 model.
Both rifles feature Ruger’s in-house, cold-forged 4140 chromoly barrel. The rifle is a 5R with a standard twist rate of 1:10. The barrel is black nitrided to resist corrosion and abrasion, combined with the durability of the hammer forging process and the characteristics of the .308 Win. Cartridge barrel life should be very long.