Educate me - SIG 55x Series


June 18, 2015, 10:15 AM
Hey guys, looking for some info on the SIG 55x series of rifles. Specifically the 551A1 and older 556 Classic. I don't own a black rifle right now, never have. But I'm planning on one soon and I'm just trying to do some research. I really like the looks of the 55x series, the long stroke piston design and the ability to have a true folding stock, but I'd love some actual user feedback.

How's accuracy, reliability, would you choose it over a quality (Colt 6920, BCM Midlength) AR?

Specifically mentioned Colt and BCM because those are the only two ARs I'm considering in addition to the SIG 551A1 or 556 Classic. Please don't recommend a different rifle.

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June 18, 2015, 11:40 AM
Well, I have the 556 Patrol with the shortened gas system.
The weapon derives from the Swiss versions and, ultimatly, the AK-47.
I like the pistol grip on it better than the AR series standard grip.
Some like this system because "it doesn't excrete where it eats" (to use a polite word which hopefully won't get censored or me suspended). This is of course due to its gas piston system. This makes it heavier than the AR series.
The folding stock system is sorta cool, and more recent versions have a attachment point mounted there for a sling. However, in reality, the actual stocks (atleast on early guns) were a bit chintzsy. The sights are nice but IMHO not as rugged/reliable as those found on many ARs, but they are replaceable.
I didn't find mine to be very accurate. Mounting an optic on it, I found it didn't like to keep the zero as well as my M4orgeries --- the rail on the receiver on the Sigs are mounted onto the receiver, screwed down or riveted, I can't remember, but this is not as reliable as making the rail an integral part of the receiver like on the AR guns.
If Sig had done a super job of it, I'd say the 556 was a better, though heavier weapon system. But the bottom line is, despite the fact I like the design better in theory, My Colt M-4 is manufactured with better quality standards -- heck, even my Bushmaster is too.
Not to say the Sig 556 won't work .... but unfortunatly I cannot claim the company put forth their best efforst in the execution of the gun, even though the design is nice.

June 18, 2015, 11:48 AM
I'm probably a bit biased.... but I love mine. It gets grabbed quicker than any of my ARs. No accuracy issues for me. Some don't like the Swiss mags on the A1 but I prefer them. (

June 18, 2015, 01:02 PM
Thanks guys, some things to think on for sure. What's typical accuracy? I'd be ok with 1.5ish MOA, I think. If I need more precision, I have bolt guns.

Zoom, have you shot any of the newer ones with a shorter piston system? What do you think of the 551A1 vs the newer 556's? I like the look of the 551A1 better and I could deal with the Swiss mags, but AR mags are everywhere for cheap...

June 18, 2015, 02:42 PM
They (Sig 55x) are ok, but not great.

Most of the differences between the Swiss rifles and the American ones are pretty clearly cost based so Sig could sell a rifle at the $1000 price point. Mine was a 2MOA rifle.

Another problem is that the warranty does not transfer to a 2nd owner.

Between the 556 and an AR, I'd have to recommend the AR, even though I don't really like ARs that much.

I know you said not to mention other rifles, but the Beretta ARX is a great contender for about $1200. You get a adjustable gas system, reciprocating CH, and adjustable folding stock for that price.


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