I am looking to get a high quality rifle and have the option of using the Law Enforcement discount through Sig.  

How does the sig 556 SWAT compare in reliability to the typical AR in the same price range?

Any other reason to go with one over the other?

I've got a 556R, not the .223 caliber 556.

I like it.  A lot.  You know its a gas piston system, not DI.  It has a two position gas adjustment screw below the front sight so you can "feed" it more gas if you shoot it enough to get it dirty enough to cause issues.  So far I've pretty much shot my AR15 and 556R side by side with the same number of rounds.  The 556R cleans up very easitly and quickly while the AR15 is dirty in all the usual places and just as long/hard to clean as ever.

I won't build another AR15.  If my wife ever decides to really start shooting I'll buy her either a SIG 556 or a SIG 516 (both gas piston with the adjustable knob/switch out front).

If you are getting it for HD or a fun gun gun then go for it. If its for duty use get a high quality AR. The 556 line is very reliable but it's a heavy gun and is not as combat friendly as an AR... Just my 2ct.

I appreciate the quick responses.

I enjoy the Gas Piston system. It makes more sense to me, I'm also a huge FAL fan so the piston is a common thing for me

As far as weight for duty use, I carry a Sig 1911, but will take the weight under advisement.

The IOP allows for purchase for off duty use.

Start here:

http://www.biggerhammer.net/sigamt/550/550techinspection/

While it's true that the American Sig 556 isn't technically on the same level of quality (Or rather manufacturing techniques of the Swiss models) it's still the Swiss design, made possible at a lower cost due to different manufacturing methods here in the US.

Having spent a lot of time with AR's and Sig's, if I had to grab only one for Doomsday, it would be the Sig.

I have a 556 and a Colt Gas piston AR. They are both ultra reliable no matter what I feed them and they are both ultra easy to clean. The edge for me goes to the AR as it's lighter by about 1.5 pounds and it is more accurate.

ditto

The Sig is a better choice for reliability and durability compared to the AR platform and I have and shoot both. I will give the accuracy advantage to the AR though. The Sig is similar to an AK in. 223 and very simple and robust in construction. It's heavy for a reason and if weight is a concern the AR has anorexic models to choose from.

Just get a SIg 516 and have the best.

Allow me to be the lone dissenter.

I think a quality AR15 will outperform the Sig 556, both in terms of reliability and accuracy, and be much more customizable. I bought a sig 556 for something different. It's fun. But I took an M4 to war and I would do it again if I got to choose.

I used to shoot AR in different models and even tried the piston action on a quality upper.  556 is in my safe now and another will join this summer.  No Ar is in my safe now have been shooting the 3 lug bolt since 08 and like it a lot.  I know it is heavier but folds down into a neater package and no worries of gas from a charging handle ruining my eyes and no sploing ever time I shoot recoil is straight back not at an angle.  I also have a Saiga in 556 I really like so simple and accurate to me is in that family.  If I want to get real accurate I can with a better caliber.

Define "reliability"?

I know that my 556 will continue firing long after most AR's have been gunked up and stopped feeding properly.

I also know, for a fact, that my 556 will eat ammo that AR's will choke on. I had a guy give me 2k rounds of .223 ammo he had after he found out it was underpowered and wouldn't run his AR. Flipped the gas valve to adverse on my Sig and she ate for free for a while...

I'll give you the accuracy part on a well-built, quality AR, but absolute reliability in all circumstances? I don't think any AR/M4 is going to rival the Sig. Yes, AR's run well if you keep them clean and lubed, but let that slip or feed it poor quality ammo and you've got instant problems...

Buy both,I've got both,AR parts can be plentiful if you are hard on your gear.The 556 is a pig but it'll fire cat turds in the form of  556 if you primer em,not finicky in any way,its a good affordable piston rifle,doesn't need 2 grand worth of extra shit,and it can fold up small enough to fit in a tennis racket case.Reliable?? mines been.no ftf issues,its tight and nothing has fallen off of it after 3 years of abuse and use. Ive got a Barret rec 7,thats my AR,i would take my sig downrange before the Barrett........the Barret is nice for accuracy,and easy cleaning. I paid 1600 for my rec 7,and paid 1050.00 for my 556 swat classic,new, the 556 is my first choice.Before all the douchebags started hording i used to let anyone who wanted to shoot my 556 shoot it. Sig should have paid me for the smiles it produced..
Hope this helps,if you get a 556 you wont regret it regardless of what the mall ninjas think............i keep mine in my work vehicle as a backup....

Buy both.
I agree with the other guys regarding the weight, accuracy, relability of the 556.
I also agree, the AR has slightly better ergonomics and can potentially be built into a lighter gun (although my experience is that most end users end up modding their AR's into 14 lb beasts).
The epic win for the 556 is the folding stock. After years of shooting AR's with tele-stocks, I forgot how nice a true folder is. The 556's  epic fail is the factory sights. Chinese contracted knockoffs. The front post is too thick, the elevation adjustments to the rear are sloppy and the yardage adjustments are VERY loose, allowing the drum to rotate completely unitentionally. They can be made to work but are better replaced.

I have both AR's and a pair of 556's and as others have said the AR platform has potential accuracy and light weight as its strong points. The SIG has better durability potential. Potential becasue anything can break but the SIG's design and build is much more robust IMHO.
I owned a select fire M16-A2 rifle for a number of years and it was pretty much trouble free with minimal issues. Cracked gas ring, "J" pin coming out of hammer, Broken extractor and a primer that fell out and got under the trigger shelf and the gun would not fire ( that was kind of unique). Granted my SIG is not select fire but it runs soooooo much cleaner and cooler it makes me dislike direct gas more & more.

I did own a 556 SWAT.  It was just too front heavy for my tastes so I swapped it for a SCAR 16. The jury's still out on whether I keep the SCAR or not. However, there's no doubt that I will be keeping mr ARs, including a S&W MP15, a DI gun.  Late last year I even picked up a Sig 516. Still breaking it in but so far I'm very pleased.  I have thousands of rounds through my ARs without any issues (although one is a LWRC piston gun).  Nor have any of my friends that I shoot with had any problems even when shooting cheap.ammo (Russian).  If you want the 556 then get it but it's not any better than any number of other guns that are available.

Personally I think that the 516 is a well crafted piston AR that I'm impressed with. However, I have less than a 1k rounds though it so I need some additional experience with it    The 556 functioned well but is over a pound heavier than the 516, and the weight isn't well balanced.  JMO

I owned a 556 since 2009, never cleaned it, never failed! The dirtier it got the better it shot! I only run a few patches down the bore, and wipe down the bolt carrier. I Tetra-Lubed it real good when I first got it, greased the rails, greased the piston, and sprayed everything with Tetra. Blow it out with high pressure air, and your good to go.

The AK design / platform which a Sig 556 basically is has been proven how durable and reliable it is in every climate, condition and use for decades.
The AR platform has also been around for quite a while and has evolved to a very good weapon system.
IMHO the AR has the edge in accuracy and can be really tuned for it. If accuracy is your main objective the AR platform is the better choice. If reliability is the most important detail the Ak / 556 is the better platform. I own both and like them all but if I had to select one it's the Sig.

Here is the deal...EVERYONE is going to piston guns...the Russians had it right in 1947...now, the Israeli Tavor, the FN SCAR, the LWRC REPR, etc, etc...all the newer military weapons are going piston...there has got to be a reason...the only reason the military still uses the M4 (direct impingement design) is due to politics...most of the people protecting the M4 & M16 are too stupid to realize that the exact same gun could be produced except with a gas piston...if you want the best of both worlds, bet the Sig 516...I hope this helps because I have wrestled this same issue.

I like my Sig, but for patrol work I would rather have an AR. Reliability with the 60 high-quality rounds you'll likely have from a clean gun is moot for a patrol gun (ie- both should shoot 60 trouble free rounds with no sweat) and the AR is lighter, more accurate and more modular. Plus, parts are easier to get and PD armorers for an AR are everywhere.

Plus almost all training classes are AR centric and most other officers would be able to use of if they had to, which for a patrol gun is a plus.

I like my Sig and shoot it a lot - but it's just a non-starter for a patrol gun.

But what if you had a piston AR?? Then you get the more reliable design, with the familiar and modular platform? Isn't that a win/win? I mean the piston AR might weigh 8oz more or something, but aren't the supposed benefits worth it?

Not really.

Piston is heavier in the worst spot (out front), and usually still less accurate.


It may be ultimately more reliable, but for a patrol rifle its moot. Both designs are still VERY reliable, and theoretically  you should be starting with a basically clean and lubed gun. Anyone who thinks a DI gun is "unreliable" is a moron and should be disregarded immediately.

Its a gun for patrol, not a gun for war. No PD is going to be shooting hundreds of rounds in a firefight- very few are even issued more then 100 rounds total. That rather neatly negates any perceived advantage a piston gun would have.

Nothing wrong with a piston gun then either, if that tickles your fancy, but in the really-real world it's not actually 'better'.

Fired at "patrol gun" distance there is no practical accuracy advantage of the AR platform over the SIG.
Reliability would be the key feature and both weapon platforms will work. The piston guns function longer in extremes such as number of rounds fired between cleaning and adverse conditions with minimal attention or action to keep running. AR's do not run well with lube and extreme cold. Piston guns run about the same in all conditions be it a FAL, AK and likely the AK piston clones in. 223.
I had a transferable M16 that I ran LOTS of rounds thru in summer & winter conditions. I had occasional stoppages but overall it ran pretty good. My FN FAL, AK, Valmet & Galil never missed a beat in the same conditions. My SIG rifles I expect the same but I can not honestly make that statement yet.
I like both & own both but if I had to choose just one of would be a piston gun.

You make a good case...the same in fact my cop buddy makes who is issued an M&P carbine...BUT, for SHTF, I mean total war and in the woods for 2yrs...certainly you'd stake your life on a piston gun?

I "like" a Sig P226 better than a Glock 17...but i choose Glock due to its reliability potential under neglect...like you say, we will probably never be in a situation to push a semi-auto AR carbine or a Sig P226 to failure...but "just in case" I like the idea of the more reliable weapon. Also, the heaviness up front makes for less barrel rise; especially if you are talking full-auto...the Sig 516 (or something like it) is what our military should be issued in place of the M4...Let the SWAT teams keep carrying the DI guns. In fact, Senator Coburn is trying to get a bill through to dump the out-dated M4...I think MANY people in decision making positions know there is a problem but they do not have the expertise to know the mechanical differences and advantages/disadvantages of DI vs piston guns...My cop buddy became defensive when I questioned DI, but he doesn't know what DI even is...he was defending the AR15, bot the gas system LOL...I sent him a pic of my 516 and he siad it was a nice AR...the fact it is piston did not register with him LOL...I think this is true for 80% of people who own and discuss black rifles.

I have both and I carry the Sig 556 for duty use.



Yes, it's heavier.  But it's built like a tank and reliable.



Eats all types of ammo without a hiccup.

My AR is more accurate then my 556, but my 556 is very picky on bullet weights and styles.


Uhhh, no? You do realise that thousands and thousands of soldiers and cops use DI guns every day right? I'd be happy with a high quality version of either, it's simply not that critical. It's the indian, far more then the arrow bud.


I've got both, and both are exellently reliable pistols. I think you're overly concerned about reliability in an almost OCD like manner. I find it just a little bit rediculous that someone would NOT carry a sig because they're worried about "reliability" :p.


It helps to put down your purse when you shoot man :)


Opinions, opinions :p. Yeah, and you seem to have already decided what's best for the military and pllice despite being neither :).

I'm glad you like piston guns, nothing wrong with piston guns. Just don't let an unreasonable complex about absolute reliability blind you to practical realities. Real life has a way of trumping theory, and real life will tell you that the gear you're obsessing over just isn't as critical as you seem to think :).

As retired military I will say, I would have rather packed the M-14 EBR (and did)

That being said...I have a 556, and an AR.  The 556 is so freaking accurate.  Yeah, it's heavier than the AR, but so reliable, accurate, and quiet.  The same loads out of both rifles are noticeably louder out of the AR and both have standard A2 hiders.

For an out of the box rifle, it's really tough to beat the accuracy of the 556.  My AR is more accurate, but I built it that way.

I like them both, but the piston system, IMO, is just inherently a better setup.