The SG 551 is the short-barrelled member of SIG’s 550 family — the Swiss service rifle adopted as the Stgw 90. Swiss-built semi-automatic examples reached the United States in small numbers and mostly through law-enforcement channels, so what turns up here is documented rifle by rifle, photographed as the exact one that ships.
The Short One in the 550 Family
Switzerland adopted the SG 550 as the Stgw 90 in 1990, and the 551 is its cut-down sibling — same rotating-bolt action and 5.56x45mm chambering in a carbine-length package. The family traits carry straight across: a folding stock, and the translucent polymer magazines that clip to one another at the side, a detail nobody else committed to quite so thoroughly.
Swiss-built semi-auto 551s were never common here. The ones that did land were early-2000s imports, and the surviving examples often carry law-enforcement markings from that route. When one reaches the bench we document the import marks and the markings as they are, and the listing photographs the actual rifle — serial, wear and all.
Common Questions
How does buying a firearm online from Old Steel Arsenal work?
Every firearm ships to a licensed FFL dealer of your choice — pick your dealer at checkout and we handle the transfer paperwork and shipping. See our FFL & Shipping page for the full process.What is the difference between the SIG SG 550 and the SG 551?
The SG 550 is the full-length Swiss service rifle, adopted in 1990 as the Stgw 90. The SG 551 is the shortened version — same rotating-bolt action and 5.56x45mm chambering, in a carbine-length package that handles far better in tight quarters.What caliber is the SIG SG 551?
5.56x45mm NATO, which also accepts .223 Remington. The Swiss military load for the platform is the GP 90 cartridge.Why are Swiss SG 551 rifles so scarce in the United States?
Very few Swiss-built semi-automatic 551s were ever imported, and the ones that arrived came in small early-2000s batches — a number of them through law-enforcement channels rather than the commercial market. That combination is why they surface so rarely on the domestic collector market.What magazines does the SG 551 use?
It takes the 550-series proprietary polymer magazines, not STANAG/AR-15 magazines. They are translucent so you can see the remaining rounds, and they clip together side by side — a signature of the Swiss design.What does the Stgw 90 designation mean?
Sturmgewehr 90 — the Swiss Army’s designation for the rifle it adopted in 1990, which the export world knows as the SG 550. The 551 is the carbine variant of that same family.What condition are these rifles in?
Each rifle is inspected and graded individually on our bench. Import and factory markings are photographed as they are, and the photos on the listing show the exact rifle you will receive — we do not use stock images.Does the rifle come with magazines or original packaging?
It varies by rifle, and the listing states exactly what is included. When original packaging, manuals or factory magazines come with a rifle, we photograph them alongside it.
Swiss-made SIG SG 551-2 SP SWAT$7,899.00rifleSG 551-2 SP SWAT .223 Remington$0.00rifleSG 551-2 SP SWAT .223 Remington$0.00