SIG AMT/PE57/550
Stoner SR-25
Barrett .50
AR15/M16 FAQs
Bushmaster Armpistol
M96 Expeditionary

SIG 550 & 551



Q, Where can I get replacement parts for an 550?

SIG Parts Service
Attn: Estes Adams
P.O. Box 2631
Auburn, WA 98071-2631

Q. What are the basic SIG 550 variants

550 - 21" Barrel
551 - 16" Barrel
552 - 10" Barrel
550 Sniper - 26" Barrel, Adjustable stock, Improved Trigger

"SP" at the end of the model number signifies that the rifle is a semi-auto only version

Q. What does the "-1" or "-2" signify in the model number i.e. 550-1or 550-2

A. The "-1" signifies 1-in-10" twist, while the "-2" is for 1-in-7" twist.

Q. What parts are interchangeable between the SIG 550 and 551?

A. For the most part all parts are interchangeable. The exception to this lies in the barrel and handguard assembly. Refer to this diagram for a better representation of which parts do interchange.

Q. Who imported the 550 series?

A. The following two companys were known to have imported 550 series
DS Arms (sporterized versions after 1989)

Q. How many 550 and 551s were imported for civilian ownership?

A. From Jodi and Bob

According to Jodi, approximately 445 SG550s and 45 SG551s were imported. Bob quotes a SIG rep. from a SHOT show encounter that says that between 34 and 37 551s were imported. Serial numbers for SIGARMS imported 550s have been seen in the mid 460 range.


Last Modified on May 11, 1999