Precise and reliable, the Sig Sauer SIG551-A1 brings 551 appeal back to the U.S. This gas-piston carbine’s diopter sights pair nicely with a Vortex 1-4×24 scope and its safety/selector is ambidextrous. The SIG551-A1 SBR is similar to the renowned SIG552. The Classic SBR version retains the comfortable handguard.Sean Utley Photo

American shooters were deprived of some great rifles by the 1989 assault rifle import ban. For me, the one that hurt the most was the SIG551. The true SIG551 is a select-fire carbine with a 14.3-inch barrel banned from import (except for LE sales) even prior to 1989. I had fired the original Swiss military SIG551 in Switzerland and considered it the best assault rifle I’d used. I haven’t changed that opinion, though I understand there are certain situations where a 7.62mm NATO rifle is desirable.

Sig’s attention to detail extends to the SIG551-A1 cocking handle, which offers good leverage should a case get stuck and allows operation with either hand. Sean Utley Photos

More recently, Sig Sauer announced the introduction of the SIG551-A1 for the U.S. market. At an MSRP of $1,986, I felt the SIG551-A1 offered other shooters a chance to own a shooting SIG551—not a collectible. I immediately requested one for testing and evaluation. But, before discussing how it performed in my tests, let me explain why the SIG551 and SIG551-A1 are such good rifles.

Gas Piston Sigs I’ve never really gotten wrapped up in gas-piston operation versus direct impingement operation as related to AR-15s/M4s. However, the SIG550 series of rifles are gas-piston-operated with a rotating bolt. With my SIG550, which I have been shooting for many years, this system has proven reliable and clean operating. In fact, I have fired thousands of rounds at times without cleaning my SIG550, yet it has continued running. It’s clean now and stuck well back in the safe. The SIG551-A1 has a two-position gas regulator. The second setting, allowing more gas, may be used when the carbine is heavily fouled or in icy conditions. My Swiss contacts have normally talked about using it in the latter situation.