Precise and reliable, the Sig Sauer SIG551-A1 brings 551 appeal…

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.

One of the reasons I think so highly of the SIG551-A1 is its folding stock, which is actually more comfortable when deployed than most fixed stocks. I also like the SIG551-A1’s paddle magazine release, which is faster to operate and sturdier than the cross-button type used on the SIG556 or the AR-15. Some will dislike that fact that the SIG551-A1 magazines cost more than M16 magazines, which may be used in the SIG556. Yes, they cost more, but I am willing to pay for them. They are extremely reliable magazines that may be coupled by a stud and slot system. They are also translucent, which allows a quick check of rounds remaining. A note on coupling the magazines: I have seen three coupled, but I normally prefer to couple two if I want a fast reload. Different instructors teach placing the extra loaded magazine on the left or right side of the receiver. I prefer the right side so the magazine does not catch on any webbed gear. Twenty- and 30-round magazines are available. I like 20-round ones in the carbine to allow me to go prone more readily, but I use 30-rounders as well.

The SIG551-A1’s standard post front sight and diopter rear sight make a good combo, allowing good open-sight accuracy to 300 yards. Since the SIG551-A1 comes with a Picatinny rail, the rear diopter sight is detachable.

I also like the SIG551-A1’s ambidextrous lever safety, which I have found one of the easiest to operate of any I’ve used. Also, the SIG551-A1’s pistol grip comfortably fills the hand well. Although I don’t normally fire assault rifles one-handed, I do frequently carry the rifle in one hand if I’m doing something with the other hand, and this pistol grip allows easy control of the rifle if held in one hand. Speaking of carrying, the SIG551-A1 has sling attachment points for a Swiss-type sling or can use a single-point or other types of CQC sling.

The SIG551-A1’s barrel uses four-groove rifling with a 1-in-7-inch twist, which means it will handle SS109/M855 62-grain ammo or MK262 77-grain ammo. It will also shoot cheaper 55-grain M193 for practice. The SIG550 series rifles have cold-hammer-forged barrels, which I believe add to their accuracy. SIG551-A1 barrels are also cold-hammer-forged, and the flash hider appears to be very close to that of the original Swiss rifles and carbines. The SIG551-A1 does not have the distinctive ball-like bulge found on the barrels of Swiss-made rifles.

Handguards on the SIG551-A1 have the same comfortable feel as those on other SIG550 series rifles. The rubber-coated cocking handle is also used on the SIG551-A1. For purists, the SIG551-A1 has the mounting point for a bayonet lug. Since I brought a SIG550 bayonet back from Switzerland some years ago, I plan to get the lug and mount it.

I find the combination of the grey finish for the SIG551-A1’s receiver with black furniture very handsome. I was shooting from a position in the shadows when testing the SIG551-A1 and found that it also offers pretty good camouflage. Summing up the SIG551-A1’s features—it’s a great combat carbine, just like the Swiss product that inspired it.

Load Comments
  • SIG blows your USA crap into the next world. German guns, ..EURO GUNS ARE GENERALLY BEST.

  • c

    very helpful review

  • Brent Sauer

    Wow that thing is way over priced.


    Updated with MSRP on page two.

  • Awlhattin O’Kaddle

    Once Again, it is insulting to Tactical-Life readers to publish this stiff without AT LEAST

  • jon

    Is there a any major difference between the Sig556 and the new 551?

  • cc19

    Trigger guard does not match the Swiss style though. Boo. They should have went all the way, or not at all IMO.

  • John

    If only this rifle had the adaptability of the AR with aftermarket products.