Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and today we're going to take a look
at sort of the base standard version of the SIG 550.
This is a 550-2, it is essentially identical
to the Swiss military Sturmgewehr 90,
just with different markings because it didn't go to the Swiss army,
it was sold on the international commercial market instead.
A big thanks to the Bear Arms reference collection in Scottsdale, Arizona,
for giving me access to bring this rifle to you guys.
This is an authentic, made in Switzerland, SIG 550.
So the story here begins ... back in the 1960s.
I should say SIG has a nomenclature system where they went with 200 series guns for their pistols,
300 for their submachine guns and 500 for their rifles.
And going into the 1960s the Swiss were armed with the Sturmgewehr 57, which was the SIG 510.
And it is this beast of a rifle,
which is quite heavy, quite expensive to manufacture,
it is chambered for the 7.5 Swiss cartridge, a big .30 calibre cartridge.
SIG knew that the trend was moving towards lighter, handier 5.56 calibre rifles.
And so in the 1960s they actually partnered with Beretta
to develop a new 5.56 calibre rifle for military use.
Now this partnership didn't really work out very well,
and the two companies after a couple of years parted ways.
SIG in the direct aftermath produced the SIG 530,
which was a very interesting rifle on its own.
We'll do a video on one of those someday when I can get my hands on one.
But it was very limited production, it was actually a gas operated, roller-locked rifle.
And it did not work well for SIG.
Within a couple of years, by the late 1960s, they had iterated to the SIG 540 instead.
And the 540 is the basis of what we have here.
The 540 was in many ways ... similar to the Beretta AR-70,
which is sort of the result of this partnership between the two companies for a while.
But it was also very similar to the Kalashnikov.
In some ways you can look at a SIG 550 under the skin as a Swiss-made Kalashnikov,
and you'll see that when we pull this rifle apart.
So SIG made a few improvements in the 1970s, and iterated their design number to 541.
And the 541 is almost identical to what we have here.
The last changes were made in 1981,
at which point the rifle was formally adopted by the Swiss military.
... SIG called it the SG 550, the Swiss military adopted it as the Sturmgewehr 90.
Now during the 1970s the rifle was kind of in a holding pattern
while the Swiss ... military was experimenting with a couple of different cartridges,
they were doing rifle trials looking at various other guns.
They developed a cartridge they called the 5.6 Eiger,
which was essentially just a Swiss-specified 5.56 NATO.
They also experimented with a 6.35 and a 6.45mm cartridge.
In fact I have a couple of videos on some of the Waffenfabrik Bern rifles that competed against
SIG's entry for what would eventually be the next Swiss military rifle.
But finally [1982] it's approved, 1982-1983 the ... contracts are drawn up with SIG,
funding is approved by parliament, it's a long process to get the rifle into production.
So before we go into [further] detail on the production,
let's take a look at what this rifle actually is internally.
[Want to see the 550 on the range? ... Check out Henry & Josh ... at 9 Hole Reviews.]
This doesn't look like an AK from the outside, but I assure you it is on the inside.
So we'll take a look at that, but first let's check out the markings here.
We have our Swiss proof mark here. We have the model designation: SG 550-2.
This indicates that this was a commercial production rifle, not military.
If this had gone to the Swiss military it would be marked "Stgw", or Sturmgewehr 90.
The "-2" is because there were two different variations made of these rifles based on rifle twist.
So a "-1" had a 1 in 10 inch twist barrel.
The -2, like this one, has a 1 in 7 inch twist.
And that's just for optimising for different bullet weights of 5.56.
And then of course we have the serial number.
This is the importer mark because this is a machine gun,
this was imported by DSA as a full-auto.
And as such we have the standard military pattern selector switch here.
Which is full, 3 round burst, semi-auto, and safe.
The magazine release is an AK style of paddle, these are a nose-in rock-back style of magazines.
These are 20 round mags, they did also make 30s that are interchangeable.
And one of the very last modifications to the pattern, done in 1981,
was the addition of these lugs on the side of the magazine
to allow multiple magazines to be clipped together.
So what we can do is put one down into the top like that,
and then snap them together like so, and you have a pair of coupled magazines.
And you can insert either one like so.
So it's a little way to carry a bit of extra ammo on the rifle
without having to go into a magazine pouch.
We have our bolt hold open and release right here.
No ... additional factory markings on the right side.
This is just the remainder of the import mark. Charging handle of course.
The iron sights are very much like an HK turret, or a diopter style of sight.
... Now these are both windage and elevation adjustable on the rear sight, which is nice.
And then they are a four position rear sight. So you have an open notch,
which does also ... have a pair of luminous dots as built-in night sights.
... That's by the way a 100 metre zero. We then have a 200 metre zero and that is an aperture sight.
And then also a 300 and a 400.
The front sight is a nice, very sharp, square post for good precision, typical of the Swiss.
Fully hooded to protect it, and then a flip up luminous night sight if you need that.
I should also point out that the front sight can also be adjusted for windage.
You can see the hash mark lining it up there.
So it's fixed on that side.
And using a screwdriver you can adjust the windage of the entire front sight base
if you need to make a significant correction there
so that you can keep the rear sight properly zeroed in the middle.
We have a pretty basic style of flash hider out here at the muzzle.
One of the other very last developments, and one of the differences
between the final adopted 550 and the SIG 541 models,
the 550 has a single basically spacer here for rifle grenades.
There's a little wire retaining clip, that puts a little bit of tension on the grenade so that
the rifle grenade doesn't slide off the front of the gun if you happen to tilt it down.
The 541 actually had two of these, and they got rid of one
as being counterproductive I suppose, at the very end of the development process.
... Up here we also have the bayonet lug. And we have a gas regulator.
This is a two position regulator, and it will snap into position there or there.
One for normal use, and one for when it's particularly dirty.
And then a couple of extra features. All of the 550s have integrated bipods.
They are not particularly adjustable bipods. They have a little bit of pivot here.
... You can't push into them very well, you can't pull back out of them very well.
But it is a bipod there, which is better than not having one.
And in addition they all have folding stocks, so you can push the button in
and the stock folds over.
And this lug right here snaps into the stock to hold it in place.
So no positive lock, it's just a tension thing.
To open it you just pop it open and pull the stock out.
Alright, enough of that, you guys want to see how this is actually an AK.
So we will take the lower off.
These are cool push pins where you push the outside ... button of the pin to unlock it.
And then you push the whole pin through.
I can pull that out, do the same thing over here on this pin.
That allows me to ...
take the lower receiver off.
There is all sorts of stuff going on in here.
We have our hammer, we have our auto-sear (or trip, or disconnect).
So in full-auto when you are holding the trigger down,
when the bolt closes the last thing it does
is push this sear down, which releases the hammer to fire.
So ... this is typical of full-auto fire control group designs.
This ensures that you don't have hammer follow with either
out of battery strikes or light strikes.
But ... you'll notice that this has a hammer spring much like an AK.
This is all essentially stamped sheet metal, it's nicely done sheet metal.
It's a little bit more complicated in some ways than an AK lower, not hugely so, but.
Now if we move on to the upper, one of the interesting things is the recoil spring
is located in the gas tube. So I still have spring tension on this with the buttstock removed.
To disassemble this I'm going to pull out the charging handle,
it's the charging handle that connects the bolt carrier to the recoil spring.
So if I take this lever, pull it down, that unlocks the handle.
That allows me to pull this handle out.
And then the bolt carrier will just slide out the back.
That is the end of the gas piston, which locks into the charging handle like so.
So here is our bolt and carrier.
That is most definitely taken from an AK.
So it's not a copy, obviously it's not interchangeable,
but this is absolutely a redesign, or a reimagining of an AK bolt and carrier system.
Same tail here ... as an extra safety to prevent hammer follow.
The only big difference here is the gas piston is not permanently attached
to the bolt carrier, like it is on an AK.
We have a stamped sheet metal upper.
A little bit of a rubber gasket here that's actually riveted into the receiver.
This is the equivalent of using the AK safety
to seal up the charging handle slot in the side of the receiver.
That rubber gasket just opens up and reseals behind the charging handle with each shot.
You can see we have some guide rails here. We have an ejector that is very similar to an AK.
Basically a pretty simple stamped upper
with things like the rear ... pin connection welded in, and the rear sight welded on.
I can take the handguard off by pulling the bottom handguard back just slightly,
that disconnects it from the upper handguard,
and then we can just lift it off.
The upper handguard comes out.
These two lock together in normal use, with these hooks locking behind those lugs.
So there is your handguard with its bipod.
We now have a gas tube, and gas piston and spring inside it.
And I can take this out by depressing this little plunger,
rotating the gas tube 90 degrees,
and then this slides out.
I can then rotate the gas plug on the inside.
And there is our gas piston.
So like I said, the recoil spring is located around the gas piston.
People often mention how this is a bad idea,
because heat in the gas piston will cause the spring to lose its temper.
That can be a thing on machine guns like the ... early pattern of the Degtyarev.
On a self-loading rifle like the SIG 550
there's really not going to be enough heat to ever cause that sort of problem.
This isn't something that's being used as a sustained-fire machine gun.
So here is the gas tube that's going to hold that spring and piston.
And our gas ... plug has two separate gas ports, one large and one small right there.
And there you go, there is the whole SIG 550,
aka Sturmgewehr 90, fully disassembled.
It really did take a while for these guns to go from SIG's prototyping
to actual Swiss military issue.
1986 the very first units actually received these rifles, and they were some recon troops
and some mountain troops, some
In 1988 the first couple of standard infantry regiments were equipped with the rifles.
It wasn't until '91-1992 that the rifles were actually in full-scale production at SIG.
And this was a major production undertaking, ... the order from the Swiss government
was for something on the order of 600,000 of these rifles.
That is essentially enough to fully equip the Swiss army
during emergency military mobilisation, which is a lot of Swiss guys with rifles.
So these would become, of course, the standard rifle for the Swiss military.
And they are widely renowned as particularly effective,
accurate, reliable, really high quality rifles.
They have a lot of good features to them, the bipods,
the rifle grenade features, actually good sights.
It's impressive to me how much better these sights are to use
than the HK apertures that are very similar in overall design.
So there would be a number of other patterns that would follow.
They made a ... 550 sniper model, which I also have a video on.
And then they would do a series of shortened rifles: 551, 552.
So there are a lot of variations on this,
but the pattern we have here is the standard Swiss army model.
Hopefully you guys enjoyed the video.
Again a big thanks to the Bear Arms reference collection
for giving me access to this one to show to you guys.
Thanks for watching.