I have previously owned a Sig 556. It was American made (I think all are?) and had swiss style furniture (not the fishgill furniture). From what I can tell, there were a few generations of this rifle:

-Earliest with an AR style buffer tube/stock
-Intermediate with Fishgill handguards
-"Newest" but ceased production, with Swiss style furniture

I am wanting to own one again, and I have found one of the early AR style tube versions for sale. More than I think it should be, but these don't come up often. Would prefer one with the Swiss style stock but havent seen one of those for sale in forever.

Questions 1: Are there any appreciable differences in functionality between the versions?

Question 2: What are most members opinions on a fair price to pay for one of the buffer tube versions in todays market?

Gen 1 556s were the fishgills. Also the Gen that has the canted rail in top of the receiver.

quote:

Originally posted by IrishWind:
Gen 1 556s were the fishgills. Also the Gen that has the canted rail in top of the receiver.

I do believe you're correct, because what threw me off about the one for sale is its a SWAT model, so I mistook it because of the rail system. Now, Im thinking there were really only two versions. One with fishgills (some seem to have side folding stocks, others not) and one with Swiss style (the 556 Classic).

First out the gate were the fixed stocks. A folder did come later. And then the Swiss style. IIRC the SWAT model with rails was either available on day one, or came a few months later. I was an early adopter of the 556, but dumped the stock and forearm before the first range trip.

And for extra points, see if the original SigTac magazine comes with it.

I have a SIG556 'SWAT' SBR that I like, but I'd really like to get my hands on a Gen2 Ambi Lower for it someday though...

Here's a pic fresh out of NFA jail...I ditched the folding/telescoping stock immediately!



If I were gonna get another SIG556, it would NOT be one of the 'Buffer Tube' equipped models. It almost seems like blasphemy IMO. I'd definitely be looking for something with 'Swiss Style' furniture and a stock of the side folding non-telescoping variety.

quote:

Originally posted by IrishWind:
First out the gate were the fixed stocks. A folder did come later. And then the Swiss style. IIRC the SWAT model with rails was either available on day one, or came a few months later. I was an early adopter of the 556, but dumped the stock and forearm before the first range trip.

And for extra points, see if the original SigTac magazine comes with it.

Interesting...so it went:

-Fishgill handguard, fixed telescoping stock. Swat versions may or may not have been available.
-Fishgill handguard, folding telescoping stock.Swat versions definitely available
-Swiss style furniture.

Does anyone know if the canted rail issue was fixed by the time the folding stock versions came out?

I think the rail issue was with the first batch or two. SigUSA was in a hurry to get them out and QC was skipped to meet a marketing deadline.

There seems to be a lot of damage around the ejection port from spent casing ejection. Is that typical?

Yes, that's typical of the 'EXTREMELY Robust Ejection' by the SIG556.

Mine is at the bottom: Upgrades are Swiss 551 handguard, MagPul CTR stock, Aurora Diopters, Swiss Bayonet + mount, and Lancer mags.

The original 556s had as was mentioned, the fish gill front handguards and a somewhat matching sliding stock. They had many internal parts that were Swiss. The later First Gen 556s had all American made parts. As I recall they did not come with rear sights. Mine was allegedly one of the first 100 made and did not have a canted rail. (My shop had a special relationship with SIG at the time, the shop owner has one of the first 50). I bought an aftermarket diopter and front sight. I also put Swiss hand guards and a Manticore grip. I put tape where the shells hit the receiver. I sold it a few years ago. The later 556s had the railed handguards, and certainly some of the 556XIs had them. My factory SBR (1 of 500 HA!!!) came with railed hand guards but I replaced them with the Swiss handguards




I Also have a factory SBR 556XI and a regular 556XI that I kept. They both have folding stocks.

Some of the early guns may have had the canted rail, but the craftsmanship was otherwise better than following iterations, IMO. The welds went downhill, and one of mine lacked welds altogether, on the forward portions of the receiver rails. Another crappy thing about the US guns was that they didn't care to time the barrel threads. I also always despised the lowers with the weird ribs on them. They're all good shooters, despite the idiosyncrasies. I'd encourage anyone in the market now to save up the extra required for a proper Swiss gun; double the money, but worth it.

I still have my 556 Classic with the side folder stock and the Diopter sights. How can you tell if the rail is canted? I have shot probably thousand rounds through it and have had no hiccups with it.

I think that by the time they got to the folding stock they had taken care of the canted rail. If you shot it that much and didn't notice anything you didn't have one.

quote:

Originally posted by kyoung:
I still have my 556 Classic with the side folder stock and the Diopter sights. How can you tell if the rail is canted? I have shot probably thousand rounds through it and have had no hiccups with it.

For me, put a red dot as far back on the upper as possible. Have the zero match the iron sights. Then slide the dot as far forward as you can on the upper. If the zero is pretty close, you are good. Mine, the zero on the red dot moved outside the front sight hood to the upper left. I also noticed the screws holding the rail to the receiver are not flush or recessed.

I am getting a QD mount for my Acog and going to mount it as far back as I can. I am putting the Diopter in front of it so I can remove the Acog and still use my open sights.

quote:

Originally posted by kyoung:
I still have my 556 Classic with the side folder stock and the Diopter sights. How can you tell if the rail is canted? I have shot probably thousand rounds through it and have had no hiccups with it.

I had an original with a canted rail. The most obvious way for me to see if it was canted was to flip that guy over and place it on the rail on a flat counter top. The cant was quite extreme and it was obvious the see the rifle lean in one direction. It near impossible however to see an optic or the sights off to one side when holding the rifle in the upright position.

I had one of the early ones with Swiss internals and barrels. Barrels were finished in the USA. It had no front or rear sighting the early fishgill stocks. I made several mods right away. Front and rear sights adde, 551 hand guards, bayonet lug and a Magpul CTR stock. Made very well no canted rails etc, etc. My only problem was I could never get it to shot better than 2 moa no matter what ammo I used. That was a very common complaint with the early 556's. But it was very reliable. I finally sold it last years after being a safe queen for 15 years.

I’ve owned around 14(?) Sig 556s from 2 of the first batch produced to the xi models. I now only have 3 xi (1 rifle and 2 xi pistols) with a 4th xi (a rifle) headed my way today.

I prefer the last - xi variants produced because it’s the only version which allows you to swap the charging handle to either side. It’s the biggest functional difference between any of the models. At this point, there doesn’t seem to be an appreciable difference in the value of an XI versus the other variants so I lean very hard towards the xi iterations. The one I bought today was $1,225 shipped to my FFL (+ gunbroker fees) and it includes the keymod hand guard (worth $275 on its own).

The only Sig 556 chambered in 5.56 I ever owned that did not run like a top and eat all kinds of ammo was one produced in 2009. I would probably avoid any that were made that year.

The one headed my way…

This message has been edited. Last edited by: Accomplice,

One just popped up for sale local to me. It has takedown pins so its not a very early model with a screw, but also has an AR style stock that is non folding. It also has a SWAT style quad rail, but the end of the barrel isn't threaded. Anyone know what model this might be? Never seen one that wont take a muzzle device. Im thinking with the non folding stock and the lack of muzzle device this is some form of state compliant model.

This message has been edited. Last edited by: dwd1985,