Sig Sauer 556 for sale
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Sig Sauer MCX Spear-LT IR Flat Dark Earth 5.56 / .223 Rem 16" Barrel 28-Rounds
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
28
Finish Per Color:
Flat Dark Earth
(0)
Sig Sauer R516G3556N16BBRZ 516 G3 5.56 NATO 30+1 16" Black Threaded Barrel, Bronze Cerakote Aluminum Receiver w/Picatinny Rail, M-LOK Handguard, Magpul DT Black Polymer Stock, AR Compatible Reduced An
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Bronze
(0)
Sig Sauer R516G3556N16B 516 G3 Mohawk 5.56 NATO 30+1 16" Black FNC Barrel, Black Anodized Alloy Receiver w/Picatinny Rail, M-LOK Handguard, Black Polymer Stock, Textured Grip, Ambidextrous
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
SIG SAUER M400-Sentry 5.56mm NATO 16in 30rd Semi-Auto Rifle w/ Romeo5 Gen II & Foxtrot-MSR Full Size Light (RM400-SDI-16B-R5FX)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
SIG SAUER M400 Rose 5.56mm 16in 30rd Rose/Black Semi-Auto Rifle w/ Romeo 5X2 (RM400-16B-ROSE-R5X2)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
Sig M400 Switchblade 5.56/.223, 11.5" Barrel, Blade Brace, Titanium Elite, 30rd
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
11.5"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Grey
(0)
SIG SAUER M400 SDI 5.56MM 16" FDE 30+1 RIFLE
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Flat Dark Earth
(0)
SIG SAUER M400 Forge
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
M400 SDI 5.56MM 16" MOSS GREEN RIFLE
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Green
(0)
Sig Sauer RM400556N16BFORGEMSGRN M400 Forge 5.56 NATO 30+1 16" Moss Green Cerakote Alloy Receiver w/Picatinny Rail, M-LOK Handguard, Magpul SL-K Black Polymer Stock, Black Polymer Grip, Sig ROMEO MSR
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Green
(0)
Sig Sauer RM400556N16BFORGE10 M400 Forge 5.56 NATO 10+1 16" Black Anodized Alloy Receiver w/Picatinny Rail, M-LOK Handguard, Magpul SL-K Black Polymer Stock, Black Polymer Grip, Sig ROMEO MSR Gen II R
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
10
Finish Per Color:
Black
(0)
SIG SAUER M400 Forge 5.56mm NATO 16in 10rd Semi-Auto Rifle, CA Compliant (RM400-556N-16B-FORGE-CA)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
10
Finish Per Color:
Black
(0)
Sig Sauer M400 Forge 5.56 Nato Rifle 16"Bbl CHF w/ Romeo-MSR Gen II Telescoping Stock Two-Stage Trigger MLOK Hg 1x30Rd Mag RM400-556N-16B-FORGE-CON
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Cerakote
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Sig Sauer SIG516 G3 5.56 NATO 11.5" Bbl Flash Hider AL M-LOK Handguard Matchlite Duo Curved BSL Brace Black Pistol w/(1) 30rd Mag P516G3-556N-11B
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
11.5"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
Sig Sauer SIG MCX 5.56 Nato Pistol Semi 5.5in Bbl NO BRACE Al MLOK Hg (1) 30 Rd Mag Rattler Pistol PMCX-5B-TAP-NB
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
5.5"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
SIG SAUER M400-Tread 5.56 NATO 16in 10rd Semi-Auto Rifle (RM400-16B-TRD-V2-10)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
10
Finish Per Color:
Black
(0)
SIG RM40016BROSER5X210 M400 556 16 OR 10R RS
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
10
Finish Per Color:
Black
(0)
M400 Tread 2.0 5.56x45 NATO 16" BBL (1)30RD Mag Black - M400 Tread 2.0 5.56x45 NATO 16" BBL (1)30RD Mag Black
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
SIG SAUER SIG516 G3 5.56 NATO 16in 30rd Black Semi-Auto Rifle (R516G3-556N-16B-CP1)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
Sig Sauer M400 Forge 5.56 Nato Pistol 11.5"Bbl CHF w/ Romeo-MSR Gen II Bsl Brace Two Stage Trigger MLOK Hg 1x30Rd Mag PM400-556N-11B-FORGE
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
11.5"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Black
(0)
SIG SAUER SIG516 G3 5.56 NATO 16in 10rd Semi-Auto Rifle (R516G3-556N-16B-CP1-10)
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
10
Finish Per Color:
Black
(0)
Sig Sauer RM400556N16BFORGEFDE M400 Forge 5.56 NATO 30+1 16" Flat Dark Earth Cerakote Alloy Receiver w/Picatinny Rail, M-LOK Handguard, Magpul SL-K Black Polymer Stock, Black Polymer Grip, Sig ROMEO M
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Flat Dark Earth
(0)
SIG SAUER M400 TREAD PREDATOR 5.56 NATO 16" BARREL 5RD JUNGLE GREEN
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
5
Finish Per Color:
Green
(12)
SIG SAUER MCX SPEAR LT RIFLE
Brand:
Sig Sauer
Action:
Semi-Auto
Barrel Length:
16"
Caliber:
5.56×45mm NATO
Capacity:
30
Finish Per Color:
Coyote Tan
Marketplace Insights
★ 5.0/5
based on 8 customer reviews across 62 products from 19 retailers
Unanimous 5-star reviews praising this rifle as a significant improvement over the Virtus, with users highlighting superior ergonomics, accuracy, and thoughtful design refinements.
What customers like
Improvement over Virtus63%
A genuine improvement over the Virtus. Small weight savings, steel QD inserts
Accuracy and handling50%
it's very accurate and lightweight, and I'm loving the ss piston
Design and ergonomics50%
balance is spot on making it easy to maneuver and shoot
Quality and reliability38%
Great quality, fit, and finish. Nice two stage trigger
Frequently Asked Questions
Sig Sauer 556 for sale
Is the Sig 556 discontinued?
Yes, SIG Sauer discontinued the 556 line, including the 556 Short SF, 556 Patrol, and 556R models. The company shifted focus to their AR-platform Tread rifles and MCX platform instead. Used 556 rifles remain available through secondary markets.
Is the Sig 556 a good rifle?
Whether it's good depends on your needs. Owners report the 556 delivers reliability, accuracy, and minimal recoil in 5.56 NATO. It's heavier than comparable AR rifles, which affects carry weight. Since SIG discontinued the line, you'll find used models on secondary markets. Modern alternatives like the MCX-SPEAR LT are currently in production.
How much is the SIG MCX 5.56 rifle?
SIG's current 5.56 NATO rifle is the MCX-SPEAR LT, with listings starting at $2,299.99 and ranging up to $2,818. Three variants are available across 19 retailers. Older MCX 5.56 models are discontinued but can be found used on secondary markets.
What caliber is the SIG 556?
SIG 556 rifles came in two main calibers. Most models, including the 556 Short SF and 556 Patrol, fired 5.56x45mm NATO. SIG also made the 556R variant in 7.62x39mm, which used AK-pattern magazines. All 556 models are now discontinued.
