My Sig556 Question thread

January 17, 2024, 09:20 PM

dwd1985

Updated the thread title because I realize I am going to have a lot more questions than just the first one. Background: I recently bought two Sig556s. First was a Sig556 Classic SWAY, second was a Sig556ER. I know the "ER" designation is an informal thing, but its an early model Sig556 with the buffer tube and mostly Swiss parts.

Question 1: On the Sig556ER I can tell by the stamps and numbering that the gas block, bolt carrier and bolt are Swiss. The charging handle is also the “upswept” design so pretty sure that’s Swiss too. The pistol grip is different from the Classic one as well, so I am pretty sure thats Swiss. Were the barrels also Swiss? Any other parts that were Swiss on these? I hear the FCG is, and comparing the two rifles, the trigger on the Sig556ER is MUCH better than the one on the Sig556 Classic.

Question 2: The gas plugs have wildly different sized holes and I dont think either of them is correct. Pics below. On the left is the plug from the Sig556 Classic. Using a large needle, it fits all the way through both holes, and the holes seem to be of identical size even though the "adverse" hole should be larger. If anything, the adverse hole is smaller. Now, compared to the Sig556ER gas plug (which should be Swiss) the holes are much smaller. The needle will not fit through either hole, but again, the "adverse" hole is smaller than the main gas system hole. The needle fits about 1/3" into the primary hole (first pic of needle inserted), and about 1/4" into the "adverse" hole (second pic of needle inserted). I know these are crappy pics. My question is pretty much just "WTF?" Why are the adverse holes smaller than the primary holes?

https://imgur.com/a/9KapFKY

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

January 17, 2024, 11:43 PM

JoshNC

Supposedly the trunions were machined from Swiss castings. The bolt and carrier were definitely Swiss on the very early guns. The barrels were FN taper bore CHF nitrided.

January 18, 2024, 08:48 AM

dwd1985

I edited my initial post, Im thinking I am going to have more questions as time goes on.

Also, I am planning to make a full (or as close to full) Swiss Sig556 as I can. If I take the upper, FCG and pistol grip from the Sig556ER, add Sig551 handguards, drop it onto the classic lower, replace the folding/collapsible stock with a Swiss stock, every part will be Swiss except the upper receiver and lower receiver, and it will have the "swiss style" sites that arent actually Swiss.

January 18, 2024, 03:48 PM

DCFD4

I had an early ER and the rail ended up being canted on it. Might want to make sure yours doesn't before you get too involved.

January 18, 2024, 05:00 PM

PGT

quote:
Originally posted by dwd1985:
I edited my initial post, Im thinking I am going to have more questions as time goes on.

Also, I am planning to make a full (or as close to full) Swiss Sig556 as I can. If I take the upper, FCG and pistol grip from the Sig556ER, add Sig551 handguards, drop it onto the classic lower, replace the folding/collapsible stock with a Swiss stock, every part will be Swiss except the upper receiver and lower receiver, and it will have the "swiss style" sites that arent actually Swiss.

Just know you're getting into diminishing returns on trying to make a US rifle more Swiss. You'll always have a US-made barrel and receivers and those will always mean they're worth less. Given the ~$4k cost of a Swiss 551-LB 16" these days, approaching anything close to half "all in" is about the max I'd recommend. The market is down right now and some folks are realizing their CC bills are more important than the shiny toys they bought over the last two years so some very good deals to be had.

January 19, 2024, 01:50 AM

dwd1985

quote:
Originally posted by DCFD4:
I had an early ER and the rail ended up being canted on it. Might want to make sure yours doesn't before you get too involved.

No canted rail issues on either rifle, all is well on both. I looked into the issue extensively ahead of time and checked them out before buying.

January 19, 2024, 01:51 AM

dwd1985

quote:
Originally posted by PGT:
quote:
Originally posted by dwd1985:
I edited my initial post, Im thinking I am going to have more questions as time goes on.

Also, I am planning to make a full (or as close to full) Swiss Sig556 as I can. If I take the upper, FCG and pistol grip from the Sig556ER, add Sig551 handguards, drop it onto the classic lower, replace the folding/collapsible stock with a Swiss stock, every part will be Swiss except the upper receiver and lower receiver, and it will have the "swiss style" sites that arent actually Swiss.

Just know you're getting into diminishing returns on trying to make a US rifle more Swiss. You'll always have a US-made barrel and receivers and those will always mean they're worth less. Given the ~$4k cost of a Swiss 551-LB 16" these days, approaching anything close to half "all in" is about the max I'd recommend. The market is down right now and some folks are realizing their CC bills are more important than the shiny toys they bought over the last two years so some very good deals to be had.

Thanks but I’m not worried. First, I got each rifle for under $1000. Second, I wouldn’t be selling the Swiss one at any point as I have been wanting one for a very long time. It would definitely be a permanent addition to my collection.

January 20, 2024, 10:36 AM

Greymann

OP, I saw you were looking for a front sight. If you don't find one mfi has flip down front sights.
I bought one but haven't installed it yet but it's good quality. Mfi has different height sights make sure to pick the correct one.

https://mfiap.com/c-254816-rif...6-classic-rifle.html

https://mfiap.com/i-14389262-m...-mail-insurance.html

.

January 22, 2024, 07:40 AM

JoshNC

quote:
Originally posted by PGT:
quote:
Originally posted by dwd1985:
I edited my initial post, Im thinking I am going to have more questions as time goes on.

Also, I am planning to make a full (or as close to full) Swiss Sig556 as I can. If I take the upper, FCG and pistol grip from the Sig556ER, add Sig551 handguards, drop it onto the classic lower, replace the folding/collapsible stock with a Swiss stock, every part will be Swiss except the upper receiver and lower receiver, and it will have the "swiss style" sites that arent actually Swiss.

Just know you're getting into diminishing returns on trying to make a US rifle more Swiss. You'll always have a US-made barrel and receivers and those will always mean they're worth less. Given the ~$4k cost of a Swiss 551-LB 16" these days, approaching anything close to half "all in" is about the max I'd recommend. The market is down right now and some folks are realizing their CC bills are more important than the shiny toys they bought over the last two years so some very good deals to be had.

PGT speaks the gospel.

January 31, 2024, 03:38 PM

Malysh

quote:
Originally posted by Malysh:
Here's my early SIG USA 556 made into a P551-2 LB clone. The US s.n. is No. 1507, so it has a very early Swiss upper receiver, gas block, perhaps barrel, etal. The gas block and barrel have Swiss markings, so I assume these early 556s utilized some real Swiss parts.

I had to wait about 2 years for SAN to make more factory semi auto PE90 or 551 semi auto receivers and had it imported here. Since the upper is the serial numbered part and the lower didn't have or require a serial number, I had the lower serialized the same as the upper. If I ever sell it the buyers will know this is not a complete matching 551 rifle. It was a long wait to get this done.

The diopter is Swiss and I had the N.H. optic rail replaced with a Swiss rail. I had the barrel modified for a replacement flash suppressor so, it still has the orignal barrel on it with no grenade ring and is two piece instead of one piece. Furniture is all Swiss. I had the entire rifle repainted with the correct paint, although the pictures do not show the tint very well.

Two gunsmiths did the modifications, Frank Hatten and Ted Marshall.

PGT is correct that modifying a US 556 rifle to a similar configuration is very expensive and in my case, very time consuming.
This conversion started around 2000 and was a couple of years until done. I probably wouldn't do it again, but it's a great rifle and very accurate, as one would expect. Much more faithful than the West Coast Armory version. I don't know if JDI was in business that long ago, and this was the only way I knew of to make a fairly accurate reproduction of the original rifle.

January 31, 2024, 07:31 PM

PGT

Such a good looking rifle! The only thing the WCA has going for it over that is the 551 rollmark.

I recall talking to Dave @ Marcolmar about buying a similar clone he built....it was like $4xxx at the time (pre-JDI). I was ready to buy until he told me they were still marked 556 and due to new rules, no remarking was possible (which was a thing with HK's). Glad I paused as I bought a JDI imported 550 shortly after for less money.

January 31, 2024, 08:26 PM

Malysh

The 556 rifle cost me $1300 new at the Hamburg PA. Cabela's. My friend and I drove down there. It was on my birthday.

I didn't have to pay cash for the SAN receiver. I have a friend who was on the A team billeted in Stuttgart, Germany, a fellow AK collector. It seems the European collectors wanted the lightweight US made lower receivers, while the US collectors (in my case, budding collector) wanted the original Swiss stamped steel lowers. Funny how that works. Here, we were disappointed SIG in N.H. decided on the aluminum ones. He took my US lower in trade and worked a deal with a gun dealer in So. Germany who ordered us factory SAN semi auto lowers. I did the import paperwork and eventually got the steel lower shipped here.

I think I probably spent another $1500 on parts and gunsmithing. So I have a little less than 3K in this rifle, which was about 1.5K cheaper than West Coast Armory was selling their offering. All it took was being patient.

Thanks for your kind comments!

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