Swiss rifles have intrigued me since the days
of my youth. I still have an old annual magazine on assault
rifles that was put out by Peterson Publishing when Guns &
Ammo magazine was at the top of their game, producing good
information for readers every month. Within the pages of that
“Assault Rifles” publication were a couple of Swiss fighting
rifles that seemed to be the ultimate in modern small arms.
However, like most things Swiss at that time, they were priced
way beyond the means of a newly-married construction worker just
starting out with a twenty-one percent mortgage and a baby on
the way. The importation of those fine rifles into the US did
not last very long, and even today the excellent Swiss SIG 550
and 551 are excellent weapons, but still priced in the US way
above the competition. However, the SIG SAUER manufacturing
plant in Exeter, New Hampshire is now producing rifles that are
very similar to the Swiss 550 and 551. Called the SIG 556, the
American-made rifle is chambered for the 5.56x45mm NATO
cartridge and accepts standard AR-15 magazines.
The SIG 556 uses a very simple and robust gas
piston system with a two-position gas regulator, which allows
the weapon to function under adverse conditions, if necessary.
The sample rifle that I tested worked perfectly with every type
of ammo that I fed it in the normal position, even when filthy,
so I had no cause to switch the regulator to position two, but
the option is there if you need it. The 556 has an ambidextrous
thumb safety that was a bit stiff to operate on the test rifle,
but has a short throw and is natural to operate, pushing
downward to fire. The buttstock, hand guard, and lower receiver
are made from a reinforced polymer, and the three-position
telescoping buttstock folds to the side for use in tight
quarters or for compact storage. The SIG 556 also comes with a
longer butt plate to extend the length-of-pull, if desired. The
weapon will fire with the stock in either position, but only
when deployed to the normal position with a drum magazine such
as the Beta C-Mag. With all straight box magazines, the weapon
will fire with the stock folded or extended. The trigger feel is
unlike that of an AR. It is smooth with about three-eighths inch
of travel, with a constant pressure throughout its travel. After
getting the feel for it, it was pretty easy to use either firing
offhand or for target work from the bench. The 556 has a very
good set of sights. The front is a protected post, and the rear
is a fully-adjustable unit with three apertures and a V-notch on
a rotating drum. I first experienced a sight similar to this on
an HK 91 many years ago. The design is similar, but the SIG
sight is superior to the HK, in my opinion. The rear sight
attaches to the integral 1913 Picatinny rail atop the upper
receiver, and is easily removed to attach a scope or other
optical sight. There is also a handy back-up rear sight inlaid
into the Picatinny rail that flips up for use. The SIG 556 wears
a relatively thin sixteen inch barrel with a one-in-seven twist
to accommodate any 223 or 5.56x45mm bullet. The muzzle is
threaded, with a closed-bottom birdcage AR-15 style flash
suppressor attached.
The SIG 556 is very easy to disassemble for
cleaning. Even after extended firing sessions, the internals of
the weapon remained fairly clean, with minimal residue to
remove. During rapid-fire shooting sessions, the thin barrel
quickly became hot, but cooled off almost as quickly, and no
point-of-impact change was noted while firing from the bench as
the weapon heated.
Critical specifications are listed in the
chart below. Linear measurements are listed in inches. Weight is
listed in pounds. Trigger pull weight is listed in pounds of
pressure. Rifling twist is listed as the length in inches of
barrel to complete one 360 degree turn on the rifling. The
weight on my sample gun is slightly higher than that listed on
SIG’s website.
Barrel Length |
16' |
Barrel Diameter |
0.57" |
Rifling Twist |
1 in 7 |
Gas Regulator Positions |
2 |
Overall Length, Stock
Extended |
34.5" to 36.1" |
Overall Length, Stock
Folded |
26.1" |
Weight, Empty |
7 lbs. 10 oz. |
Buttstock |
Folding, Polymer |
Length-of-pull |
11.63" to
13.25" |
Handguard |
Polymer |
Trigger Pull |
5.5 lbs. |
Magazines Supplied |
One 30-round |
For accuracy testing, I mounted my mule, the
Leupold Mark 4 8.5 to 25 power target scope using an ArmaLite
one-piece mount. Accuracy testing was done at 100 yards, with
the results shown in the chart below. Group sizes are the
average of three-shot groups at that distance. Group sizes are
listed in inches. Velocity testing was done with the chronograph
twelve feet from the muzzle at an elevation of 541 feet above
sea level, approximately. Temperatures hovered around the
eighty-two degree Fahrenheit mark during all testing. Velocity
readings are the average of several shots fired, and the results
are listed in the chart below. Velocity readings are listed in
feet-per-second (fps). Bullet weights are listed in grains. FMJ
is a full metal jacket bullet. HP is hollowpoint. ASP and FHVL
are specialized bullets as loaded into ammo produced by Extreme
Shock Ammunition. TSX is a Barnes Triple Shock homogenous
copper hollowpoint bullet. AP is a full metal jacket bullet with
a steel-tipped lead core. The handload listed uses the TSX
bullet with 24.5 grains of Ramshot TAC powder, a Remington small
rifle primer, and Winchester commercial .223 Remington cases.
Ammunition |
Bullet Weight |
Velocity |
Accuracy |
American Tactical FMJ |
62 |
2989 |
|
Hand Load TSX |
62 |
2799 |
1.50" |
Winchester USA FMJ |
55 |
2928 |
|
Winchester USA FMJ |
62 |
2912 |
1.62" |
Buffalo Bore HP |
69 |
2867 |
1.25" |
Extreme Shock ASP |
100 |
1187 |
|
Extreme Shock FHVL |
62 |
2798 |
|
Samson FMJ |
63 |
2812 |
|
Black Hills HP |
69 |
2727 |
1.12" |
Wolf Gold HP |
75 |
2579 |
1.38" |
Lake City SS109 AP |
62 |
3031 |
2.63" |
As shown in the chart, accuracy was very
good. The loads for which velocity readings are listed without
accuracy data is due to not having enough of that particular
ammunition available to me for thorough accuracy testing. Some
of the loads tested displayed very consistent accuracy from the
bench. Reliability was flawless during all phases of testing.
Every cartridge fed, fired, and ejected perfectly. Case mouths
were dented, and a small indentation was also noted on the body
of each empty case, which might be a concern for hand loaders.
However, the case mouths can be straightened by the sizing die,
and the body dent is of no concern to me. Ejection was to the
right and slightly forward.
The SIG 556 is a fine fighting rifle. While
priced right along with the top-tier AR-15 rifles on the market,
it is every bit as good, and some folks prefer this type of
weapon to an AR. It is certainly a reliable, accurate weapon,
and it can use any magazine that will work in an AR-15. I would
love to get my hands on a select-fire version of the SIG 556, to
see how this thing runs on full-auto. Judging by the recoil and
handling characteristics of this semi-auto version, it will do
quite well. The folks at SIG SAUER have produced a fine
Swiss-designed rifle that is built in the USA, making it
affordable to most of us who either cannot or will not pay the
price of a good pickup truck for the Swiss version. SIG lists
the MSRP of the Patrol Rifle at $2000 US, but they are selling
around here for much less, making the price very competitive
with other quality fighting rifles. The SIG 556 Patrol Rifle
comes in a hard plastic case with one thirty-round magazine,
extra thicker butt plate, and instructions.
Check out the SIG 556 and other SIG products
online at www.sigsauer.com.
Jeff Quinn