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SI designs rugged, user-focused firearm components and optics. They make accessories like slide plates, charging handles, barrel clamps, red dots, and shotgun parts.
All SI Products (2,384)
Sig Sauer 320XF-9-BXR3-RXX P320X 9mm 17+1 X-Ray Sights Romeo-X Optic Black
Sig Sauer P320XC 9mm 15+1 X-Ray Sights Romeo-X Optic Black/Nitron Slide
Sig P320AXG LEGION 9MM 21R Romeo-X Optic XSeries Trigger Gray Grip
SIG P226 X5 Legion 9MM 20RD Romeo-X Optic Gray Cerakote TXG Grip
Sig Sauer AMPCBBP320XCA P320 XCarry .177 Airgun 21rd Black Polymer
Sig Sauer AIRP229RX177BLK P229 Blowback CO2 Air Pistol .177 16rd
Sig Sauer Cross 300 Win Mag 24" 6-Rounds
Sig Sauer W365-9-BXR3P-MS P365 9mm 3.1" Nitron Semi-Auto Pistol
Sig Sauer W365-9-BXR3P P365 9mm 3.1" Nitron Semi-Auto Pistol
Sig Sauer P320XTEN 10MM 15+1 X-Ray3 Sights Topographic Cerakote Slide
Sig Sauer Cross .308 Win 16 in Threaded Barrel Black Folding Stock 5rd
Sig Sauer CROSS 243 Rifle 5+1 16.5" Black Folding Stock 11.5" Handguard
Sig Sauer SORM1710 Romeo-M17 1x24mm 2 MOA Red Dot Sight Black
Sig Sauer P365 XMacro 9mm Luger Semi-Auto Handgun with Romeo-X Optic, 17+1 Capacity
Sig SAUER P365X-Macro 9mm 3.7" 2x17rd Pistol With Romeo-X 365XCA-9-BXR3-RXX
Sig SAUER P365X Pistol 9mm Romeo-X XSeries (2) 12rd (365X-9-BXR3-RXX)
Sig Sauer SURG556 5.56mm Rifle Suppressor Flat Dark Earth Cerakote
Sig SAUER P226 X-Series Legion Carry Size 9mm 3.8in 3x10rd SAO Pistol
Sig Sauer P226-XCarry Legion SAO Handgun 9mm Luger 10rd Magazines(3) 3.8 Barrel Optic Ready Legion Grey Cerakote
Sig SAUER P226 X-Series Legion 9mm 4.4in 3x10rd Legion Gray SAO Pistol
Sig Sauer P226 XCarry Legion Handgun 9mm Luger 10rd Magazines(3) 3.8 Barrel DA/SA Optic Ready Legion Grey Cerakote
Sig Sauer 8901534 P320 Slide Assembly with Romeo-X Pro & Compensator
Sig Sauer BuckMaster 3-9x50 Rifle Scope with BDC Reticle and 50mm Lens
Sig Sauer P320 Xten CarryComp 10mm 3.8in Black 15rd Striker Fired
Sig SAUER Romeo M17 Coyote Tan Reflex Sight 2/32 Moa Circle Dot NVG-Compatible
SIG 1911 XCarry 45ACP 4.25" Barrel XRAY-3 Sights, G10 Coyote Grips, 8RD Magazines
Sig Sauer 1911 XCARRY .45 ACP 4.25" Barrel XRAY3 Sights 8RD G10 Grip Black
Sig Sauer SOTD65114 Tango-DMR 5-30x56mm 34mm Tube Illuminated Reticle
Sig Sauer SOTD65113 Tango-DMR 5-30x56mm 34mm Tube MOA Reticle Black
Sig Sauer SOTD63114 Tango-DMR 3-18x44 34mm MRAD DEV-L 2.0 Black
Sig Sauer SOTD63113 Tango-DMR 3-18x44 34mm Tube MOA Reticle Black
Sig Sauer SORX1000 Romeo-X Reflex Sight 1x24mm Circle Dot Black
Sig Sauer WRMPX-4B-9-SBR-35 MPX SBR 9mm 4.5 In 35+1 Black Folding Stock
Sig Sauer P320-XTEN 10mm Auto Recoil Spring Assembly 8901519
Sig Sauer Whiskey 4 SOW43004 3-12x44mm 30mm SFP Matte Black Scope
Sig SAUER Whiskey 4 3-12x44mm Rifle Scope 30mm Tube SFP Quadplex Reticle
Sig SAUER Romeo-X Compact Red Dot Sight 24mm Circle Dot Reticle Black
Sig Sauer E9MMB1ROSE50 Rose 9mm 115gr FMJ Ammo 50 Rounds
Sig Sauer E9MMA1ROSE20 Rose 9mm 115gr JHP Ammo 20 Rounds
Sig Sauer P365 AXG Legion 9mm Compact Pistol: XRAY3 Sights, 3x17-Round Mags
Sig Sauer 9389TXR3AMBI P938 9mm 3" Rosewood Grip Two-Tone Micro-Compact
Sig SAUER P320 Carry 9mm/40/.357 Black Medium Grip Module (8901514)
Sig Sauer P226 XCarry Legion Handgun 9mm Luger 18rd Magazines(3) 3.8 Barrel SAO Optic Ready Legion Grey Cerakote
Sig Sauer P226 XCarry Legion Handgun 9mm Luger 18rd Magazines(3) 3.8 Barrel DA/SA Optic Ready Grey Cerakote
Sig Sauer P226-X Legion SAO Handgun 9mm Luger 18rd Magazines(3) 4.4 Barrel Optic Ready Legion Grey Cerakote
Sig SAUER P226 9mm 4.4in 18rd Semi-Automatic Pistol (226X-9-LEGION)
Sig SAUER P320 Legion 9mm Luger 3.9in 10rd Pistol 320AXGF-9-LEGION-10
Sig Sauer Tango-MSR LPVO 1-6x24mm Rifle Scope
About SI
Headquarters
Established
-
Country of Origin
USA
History & Heritage
SI began as an American aftermarket parts maker aimed at providing functional, affordable upgrades and accessories for shooters. Over time the brand expanded its offerings across pistol, rifle, and shotgun platforms, becoming known for practical designs and broad compatibility.
Notable Products
Popular items include charging handles, slide adapter plates, red dot sights, barrel clamps, and shotgun conversion components.
Why Choose SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity.
Hot SI Items June 2026
Trending right now based on the last 30 days of TheGunDock orders + page views.
SIG SAUER 322C-ROSE-RS P322 Rose 22 LR 4" Black Anodize Semi
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
Sig Sauer W365XL-9-BXR3P-MS P365 XL 9mm 3.7" Nitron Semi-Aut
Sig Sauer Tango-MRS Compact Rifle Scope 1-6x24 30mm SFP BDC6
Sig Sauer Cross Sawtooth Rifle 6.5 PRC 22 inch Moss Green Fo
Sierra Bullets 4540C 7mm 0.284 Caliber 140 Grain Tipped Boat
SilencerCo AC1278 ASR Black Nitride 9/16"x24 LH Threads 30 C
Sig Sauer W365XL-9-BXR3P-RXX P365 XL Romeo-X 9mm 3.7" Nitron
Shop SI Products
Sig SAUER MCX-SPEAR 6.8x51mm SBR 13in Semi-Auto Rifle RSPEAR
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
Sig Sauer P320 FLUX 9MM 3.9" 30RD Legion 320
Sig Sauer SLH300TIQD 300 Blackout Titanium Suppressor
SilencerCo Velos LBP 5.56 NATO/.223 4.76 In Low Back-Pressur
SIG SAUER MCX Spear SBR 7.62x51mm 13" Nitride NFA
Sig Sauer P365X Macro Tacops 9mm 3.7" 17rd Pistol
Sinclair INTERNATIONAL DIAL INDICATOR .001
Sig Sauer ROMEO1 Black Shroud Kit SOR1SK001: Medium Size, Ne
Sig Sauer 8900823 LTXG Grip Module Laser Engraved P320-X Car
Sig Sauer MCX-SPEAR LT AR Conversion Kit 5.56 NATO 11.5" Bla
Sig SAUER MCX 5.56 NATO 16in 30rd IR Cerakote FDE Rifle RMCX
SI News & Articles
Firearm Shipping Restrictions by State (2026 Update)
State-by-state guide to firearm and ammunition shipping for online buyers and FFL dealers. Current as of May 2026. Cover...
Damaged in Transit: How TheGunDock Handles Shipping Claims on Firearms and Ammo
When a firearm or ammo shipment arrives damaged, the claim process matters. TheGunDock walks through what to do, what we...
The Springfield KUNA: Roller-Delayed 9mm Pistol That's Shaking Up the PDW Market
The Springfield Armory KUNA — a roller-delayed 9mm pistol built in partnership with Croatia's HS Produkt — has becom...
The Strait of Hormuz: 2,500 Years of Trade, Arms, and Conflict
A twenty-one-mile-wide choke point has shaped the movement of goods — and weapons — across half the ancient and mode...
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