Buy SI Online
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 (2,388)
Sear Spring
Sinterfire SF300BLK110RHA 300 BO Rha 110G LF 50
SINTERFIRE SF300BLK110GL-C 300 BO GL 110G LF 50
SINTERFIRE SF22355RHA(50) 223 RHA 55G LF 50
Sinterfire SF22355GL-C 223 GL 55G LF 50
SINTERFIRE SF22350NXG 223 50G Lead Free Tactical Ammo
SIG SAUER RM400-556N-16B-FORGE-MSGRN M400 Forge 223 Rem | 5.56 NATO 16" Moss Green Cerakote
SIG SAUER RM400-556N-16B-FORGE-CON M400 Forge 223 Rem | 5.56 NATO 16" Concrete Gray Cerakote
SIG SAUER RM400-556N-16B-FORGE-CA M400 Forge 223 Rem | 5.56 NATO 16" Black
SIG SAUER RM400-556N-16B-FORGE-10 M400 Forge 223 Rem | 5.56 NATO 16" Black
SIG SAUER RM400-556N-16B-FORGE M400 Forge 223 Rem | 5.56 NATO 16" Black
Sig Sauer Handgun Magazine for Subcompact P365 with Finger Extension 9mm Luger 10/rd BULK
SIG SAUER 365XCA-9-FBZXR3 P365 X-Series 9mm 3.7" 2-Tone Bronze Semi-Auto Pistol
SIG SAUER 1911XCA-45-FBZXR3P 1911 X Carry 45 ACP 4.2" 2-Tone Bronze Semi-Auto Pistol
SIG SAUER SORJ8T811-3 Romeo 8T-AMR Combo Flat Dark Earth Uses (1) CR123A Battery 1X40 Full Size Red Dot Shroud JULIET3T-AMR 3X22 Magnifier 3X22 JULIET3T-AMR MAGNIFIER
SIG SAUER SORJ8T801-5 Romeo 8T-AMR Combo Black Uses (1) CR123A Battery 1X40 Full Size Red Dot Shroud JULIET3T-AMR 5X24 Magnifier 5X24 JULIET5T-AMR MAGNIFIER
SIG SAUER SORJ8T801-3 Romeo 8T-AMR Combo Black Uses (1) CR123A Battery 1X40 Full Size Red Dot Shroud JULIET3T-AMR 3X22 Magnifier 3X22 JULIET3T-AMR MAGNIFIER
SIG SAUER 211F-9-GTO-R3P P211-GTO RXSL 9mm 4.4" Bull Barrel Nitron Semi-Auto Pistol
SIG SAUER 8902056 P365-AXG Grip Module Coyote 1913 Picatinny Rail Medium Grip Size 8902056
SIG SAUER 320F-9-BSSP-TACPRO P320 Full TACPRO 9mm 4.7" Nitron Semi-Auto Pistol
SIG SAUER 365XCA-9-T-COMP P365 X-MACRO COMP 9mm 3.1" Stainless Semi-Auto Pistol
Sightron S6 10-60x56 34mm Snap Focus Tactical Scope
Sightron S6 10-60x56 34mm Snap Focus Tactical Scope
SIGHTRON SCOPE S6 10-60X56 ED 34MM ILLUMINATED
Sig P365 XMacro Handgun 9mm Luger 17rd Magazines (2) Threaded Barrel Two-Tone Tan XSeries Slide with Optic
Sig Sauer CROSS .308 Win 16 In Brushed Stainless Steel Bolt Action Rifle
Sig Sauer 516 G3 Mohawk 5.56 NATO 16" 30rd Tele Stock Bronze Rifle
Sig Sauer P365 9mm 21Rd Optics Ready Black Tactical
SIG SAUER 365XCA-9-COMP-MS P365 X-MACRO COMP 9mm 3.1" Nitron Semi-Auto Pistol
Sig Sauer ROMEO 8T AMR 2.0 Red Dot 40mm Objective QBCD 2.0 Reticle 1913
Sig Sauer W211F9GTORXSL 9mm 4.4 In 21+1/23+1 Black Comp Sig-Lok Pro
Sig Sauer P226 9mm 4.4 In 18+1 Black
Sig Sauer W211F9GTO 9mm 4.4 In 21+1/23+1 Black Comp
Sig Sauer M17 9mm 10Rd FDE Night Sights Tactical
Sig Sauer P320 9mm 10Rd Optics Ready 3.9 Barrel
SIG RS 5BB ROSE 2.93" BLK/ROSE
SIG SAUER P365 FUSE COMP HGA 9MM 3.7IN BBL OR XRAY DAY/NIGHT POLY GRIP MOD 1913 RAIL 3-10RD MAGS
SIT Rifle MOA 16x16in 8 Pack White
Sig Sauer P365 XMacro Hush Puppy Semi-automatic Striker Fired Polymer
SIG SAUER 320XF-9-MOD-RXSL P320 M.O.D. 9mm 3.9" Matte Black DLC Semi-Auto Pistol
SIG SAUER 320XF-9-MOD-10 P320 M.O.D. 9mm 3.9" Matte Black DLC Semi-Auto Pistol
SIG SAUER 320XF-9-MOD P320 M.O.D. 9mm 3.9" Matte Black DLC Semi-Auto Pistol
SIG C243VP7020 VARMAGEDDON 243 70G 20/10
Sig Sauer Varmageddon .22-250 Rem 55gr FB Tipped 20rd Ammunition
SIG C223VP5520 VARMAGEDDON 223 55G 20/10
Sig Sauer Varmageddon .223 Rem 40gr Hollow Point 20 Rounds
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.
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
Sig Sauer 2401191R Picatinny Stock Adapter for AR-15, Alumin
Sig Sauer SORX1080 24MM Black Pro Optics Ready Sight
Sig Sauer W365XL-9-BXR3P-RXX P365 XL Romeo-X 9mm 3.7" Nitron
Sig SAUER 365XF-9-CFO-2A P365 Fuse 9mm 4.3" Nitron Semi-Auto
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...
Ready to Shop SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
Browse All Products