SIG SG 550: Swiss service rifle from the 1990’s

SIG SG 550 with optional second magazine
SIG SG 550 with optional second magazine (Photo: XY)

The SIG SG 550 is a Swiss rifle manufactured in the 1990s for the Swiss Army’s need. The Swiss Army has used a powerful 7.5mm cartridge since the turn of the century. In recent years it decided to investigate a lighter caliber and asked both its own Federal Arsenal at Berne and the SIG Company to develop some new rifles in smaller calibers.

As a result, both establishments produced prototypes in 5.56mm and in a new 6.45mm caliber; government testing eliminated the 6.45mm round. The SIG SG 550 became the Swiss service rifle in 1990.


The SIG SG 550 is their answer to the request, and as well as being formally adopted it is now available for commercial sale to approved customers. It is a conventional gas-piston-operated rifle using a rotating bolt inside a bolt carrier. High-quality plastic material has been used for the folding stock, the fore-end guard, and the transparent magazine. Two lengths are available; the longer model is the ‘Assault rifle’ while the shorter weapon was known as the ‘Headquarters weapon’ and, with the butt folded, it was used in the submachine gun role.

SIG SG 550 parts
SIG SG 550 parts (Photo: XY)

The sights are an aperture rear and blade front, with luminous dots for night sighting, mounting points for a telescope, or various electro-optical sight units. There is a three-round burst facility, plus single shots or full-automatic fire, and a light bipod can be fitted to steady the weapon when used in the squad automatic role.

User experience

Speaking generally, SIG SG 550 is a good rifle. It’s typical Swiss high quality, although a little heavier than similar service rifles. Part of that weight increase is that it has a somewhat longer barrel, which gives it a small increase in range compared to the AK-74 (and obviously a greater increase in range than the M4 Carbine).

Switzerland is a mountainous country with its own demands on shooting, and the Swiss have learned to cope with that and built a reputation for marksmanship in doing so. They desire to keep that high level of marksmanship, and so the SIG SG 550 was designed with all that in mind. It also has better ergonomics than some similar rifles.

How does the SIG SG 550 compare to the other assault rifles?

The SIG 550 is very finely machined. Of course. It’s Swiss. That automatically makes it nicer than any other AK derivative. And more expensive. Yes, I do consider the 550 a loose derivative of the AK. None of the others comes close. So its main competition is the AR/M16.

SIG SG 550 with additional gadgets installed
SIG SG 550 with additional gadgets installed (Photo: XY)

The piston system of the SIG SG 550 makes shooting a much less pungent experience. All the hot gas gets dumped out over the handguards. In the AR, it goes back into the receiver, heating it and blowing through the gaps into the shooter’s face. The piston does add weight, out at the end of the gun where it’s most noticeable. AR shooters like lightweight handguards to cut weight even more. The SIG SG 550 swings much more slowly, or at least feels like it does.

The stock AR trigger is worse, but that has spawned a whole market for replacements. Some of them are very good, better than the SIG. So I would say there is no better-issued rifle than the SIG SG 550. But a customized AR makes a better “race gun” for competition shooting.

Technical specifications

Manufacturer: Schweizerische Industrie Gesellschaft (SIG), Neuhausen-Am-Rheinfalls, Switzerland
Type:  gas-operated, automatic, magazine
Caliber: .223 (5.56mm)
Barrel: 14.05 in (357 mm); or 21 in (533 mm)
Weight (empty): 8.26 lbs (3.75 kg); or 7.36 lbs (3.34 kg)
Magazine capacity: 20, 25, or 30 rounds
Cyclic rate of fire: 750 rounds per minute
SIG SG 550: Technical Data
SIG SG 550: Technical Data (Photo: XY)
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