SiG 556 vs. ??

[epete]

Hello, I'm new to this forum. I am in the market for a piston operated rifle, does anyone have first hand experience with a Sig 556? How would it compare with some of the piston operated AR's, such as POF or Leitner-Wise? I've scoured the internet and come up with very little (useful) information. Thanks!

[fivepointoh]

check out ARFCOM in the link below as they have plenty of reviews about the SIG but w/ that said I would go w/ a Rob Arm XCR.

Here's the link to click on to see all the topics in the General Firearms Discussion.

http://www.ar15.com/forums/forum.html?b=6&f=2



Now a guy just did a somewhat formal and very informational thread comparison between the XCR, 556, and L-W SRT and here is what he had to say.

http://www.ar15.com/forums/topic.html?b=6&f=2&t=216872




Here is another comparison between the XCR and 556


http://www.ar15.com/forums/topic.html?b=6&f=2&t=217569



Hope this helps some.

[JoshNC]

I love my 556. I converted it to 551-like configuration using a Swiss 551 semiauto lower, front handguard, and gasblock.

Here is the link to my review and pictures.

[epete]

Thanks! That was exactly what I was looking for. I had forgotten the XCR, this does not make my decision any easier.

[PalmerB]

Hello, I'm new to this forum. I am in the market for a piston operated rifle, does anyone have first hand experience with a Sig 556? How would it compare with some of the piston operated AR's, such as POF or Leitner-Wise? I've scoured the internet and come up with very little (useful) information. Thanks!

I bought the 556, and I still prefer my AR (non-piston). My review from the Sigforum:

The Sig 556 in review

Part one- Buying

I had a choice between a Sig 556, the Robinson Armament XCR and an AR-15. The Sig was $1295, the Robinson Armament $1500 and AR’s vary in prices, but it is about $1,000 for a decent one off the rack. I bought the Sig because I already have an AR, and because of Robinson Armament’s history with what I consider unfulfilling and relative abandonment of the M96.

Upgrades for the Sig 556 included the following: Magpul CTR stock with riser ($120) and flip up back up iron sights ($250), I had an extra receiver extension for the CTR stock, but if you don’t have one ($40).

I use rails for a few things:

1. mounting lights
2. Mounting a bipod
3. Free floating the barrel
4. Placing a sling without putting pressure on the barrel. (How the heck did we peg the 500 meter target routinely with a military loop sling, I am not sure).


I do not know if floating a piston barrel assembly will improve accuracy or not, but on a direct impingement AR it works.

Part two – cleaning

Years of experience with the AR-15/ M-16 have resulted in efficient, quick and purposeful disassembly, cleaning and reassembly.

I would say the two are even in this point, except cleaning the buffer spring in the AR is easier than cleaning the piston and spring in the Sig.

Only minor stressors with the 556 are replacing the handle for the bolt during reassembly and disassembly/ reassembly of the 556 firing pin. The AR-15 assembles easily.

Part 3 – Design

I don’t mind the that the Sig 556 came with the funky stock. I figure it is like plastic Glock sights, they use cheap ones because they know must of us will replace them anyways. Same with this stock.

The Sig has a rubber like seal that moves around the charging handle when the bolt is pulled. This may eventually wear. The AR-15 has an ejection port cover that flips open when the weapon is fired, but it is also my experience that this doesn’t form a very tight seal either. The Sig 556 is heavy.

The AR-15 has the charging handle in the rear. South paw/ right hand debate aside (especially since I have read about right handed shooters using left handed rifles because they feel it is easier to operate the bolt), the problem with a side charging handle is that your hand may rub on some wide base optics like the Eotech.

The AR-15 has a chrome lined barrel. The Sig 556 is not. Sig feels it is not needed. The 556 did come with a 1/7 twist barrel, but so do some AR’s. The Sig did have a nice 1/2x28 thread job with a good shoulder.

The Sig 556 does have one of the nicest factory triggers on a semi-auto rifle. In comparison, a good two-stage trigger like the Rock River begins at about $100.

The Sig loses big time points on the grip. This is the greatest oversight in the design, is not making a grip that mates evenly with the trigger guard. I hope an aftermarket grip comes out soon.

The AR-15 uses an ejector in the bolt and a spring to push the ejector. The Sig 556 has a fixed ejector and when the cartridge is pulled back by the bolt it strikes the ejector. I have never had a problem (Knock on wood) with an AR-15 ejector failing, but this is a notable difference in design.

Part 4 – shooting

The Sig 556 is heavy, especially in comparison to a little SBR AR-15. It shot flawlessly without error. I haven’t been able to shoot more than a few hundred at this time, but I’ll defer to the Sig Arms rep who told me they have shot 40,000 through one without incident.

The Sig 556 sounded louder suppressed than the AR-15 with the same suppressor. Our meter wasn’t working well that day, and we’ll need to try another to bring specific decibel numbers.

The AR-15 has also shot flawlessly. We have done some durability tests with it, buying a new one and shooting over 1,000 cartridges through it without cleaning or lubing. I took one to two local back to back shoots with a suppressor on it and encouraged everyone to dump everything they had from Wolf to XM-193 through it. The only error experienced was the magazine catch became stuck open from a large chunk of carbon, and non Magpul followers would gum up in the magazines.

I consider a Magpul follower to be the greatest $2 upgrade to either rifle. The level action of the design improved feeding. Great design.

The Sig shot ½ as precise as the AR-15. I attribute this to a few things:

1. I have been shooting AR’s for years and I learned in the military.
2. I had an aimpoint on the AR and an Eotech on the Sig556, I normally shoot the aimpoint
3. The AR-15, although an SBR, had a free floated barrel.

Part 5 – recommendation

I consider the 556 a good rifle, but if it comes down to only having an AR with optics, or buying a 556 I would go with the AR-15 easily. If you want a Sig 556 because you have always wanted one of the Sig 550 series rifles, do it. It is a nice rifle. I won’t be selling mine.

I have also lost interest in piston design AR-15’s, especially when you can buy a 556 rifle for about the price of an AR-15 piston upper.

For the Troy sight, I had to machine and recoat the posterior section of the rail a little to fold it down as far as it would go and not have it rest at the end of the rail. AN AR-15 receiver is narrow at the back and does not have this problem with the Troy sight.

[TOrrock]

Palmer, thanks for your review.

I have an opportunity to buy one, the dealership I used to work for got one in and called me yesterday.

I swung by today to take a look. My thoughts about the grip (what the hell were they thinking/who the hell implimented that?!) and balance echo your experience.

I'd love to have a pre-89 SIG 550, but I don't think I'll ever get one.

If SIG come out with a side folder thats similar to the original rifle for the 556, I might have to jump.

It won't do anything my Colt 6920 won't, but it is different, and it does have high CDI factor going for it.

[PalmerB]

I only have it to have it.

I have experimented putting a scope on it. I will probably put a lower power 30mm tube scope in a Larue mount or a Acog and use it with a Yankee Hill (Harris) Bipod adapter + Harris Bipod as a SPR.

I have even tried selling it to a few friends who wanted to buy one, but because they are friends, I pull out an AR-15 and explain to them why I like the AR15 better. Then they end up buying an AR-15 and I still have the Sig 556.

Another gentleman I talked to has the same opinion, but he recommended that I just keep it to keep it as a possible investment.

So there it is.

[C4IGrant]

Hello, I'm new to this forum. I am in the market for a piston operated rifle, does anyone have first hand experience with a Sig 556? How would it compare with some of the piston operated AR's, such as POF or Leitner-Wise? I've scoured the internet and come up with very little (useful) information. Thanks!

I wouldn't dig a hole with the SIG 556 personally. The only gas piston uppers I would even consider are POF, HK and the Magpul Masada (when it comes out). Truth be told, I am not really a gas piston fan, but do believe that they have their place.



C4

[awmp]

good info, I was looking at a 556 and I have heard so many issues with just zeroing in the weapon I had put it off, I think I'm going to wait a little longer for my purchase

[Ed L.]

I love my 556. I converted it to 551-like configuration using a Swiss 551 semiauto lower, front handguard, and gasblock.

Here is the link to my review and pictures.

Nice looking gun, but you have an extra http in your link so it comes up as broken.

Below is a link to the pics and thread. As someone in that thread wrote, this is the gun that Sig should have brought out. The Sig556 does nothing for me.

http://m4carbine.net/showthread.php?t=3789