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 (2,384)
Sig Sauer 1300675-R Trigger Bar P320
Sig Sauer Alpha1 Tactical Scope Ring Set 30mm Cantilever Aluminum
Sig Sauer SOZ71001 Zulu7 10x42mm Graphite Open Bridge Binoculars
Sig Sauer Electro-Optics Romeo7 Red Dot Sight 1x30mm 2 MOA
Sig SAUER P250/P320 Full Grip Module 9mm/.40AUTO/.357SIG Black Small
Sig SAUER 250/320 FS Medium Grip Module Black Synthetic 9/40/357 - GRIP-MOD-F-943-M-BLK
Sig Sauer P250 P320 Full Size Grip Module Large Black Poly 9mm 40
Sig Sauer GRIP-MOD-C-943-M-BLK Compact Grip Module P250/P320 9/40/357 Black
Sig Sauer P320 P250 Large Grip Module 9mm 40 Auto 357 SIG Black
Sig Sauer P250/P320 Compact Grip Module 45ACP Small Black - GRIP-MOD-C-45-SM-BLK
Sig Sauer GRIP-MOD-C-45-M-BLK Compact Grip Module P250/P320 45ACP Black
Sig Sauer E40SB250 Elite Ball 40 S&W 180 gr 985 fps FMJ 50 Bx
Sig Sauer E10MB150 Elite Ball 10mm Auto 180 gr FMJ 1250 fps
Sig Sauer Elite Ball 9mm 124gr FMJ Ammo 50rds E9MMB2-50
Sig Sauer Elite Ball 9mm Luger 115gr FMJ Ammo 50rd
Sig Sauer P320 Compact .45 ACP Night Sights Black
Sig Sauer E45BA350 Elite Ball 45 ACP 230 gr FMJ 830 fps
Sig Sauer PKIT-SRT-226-227-229 Short Reset Trigger Kit
Sig Sauer P320/P250 45ACP 10RD Magazine
Sig Sauer Magazine P250/P320 45 ACP Compact 9 Rounds Black Finish
Sig Sauer Mag P250 P320 45 ACP Sub Compact 6 Rounds Md: MAGMODSC456
SigTac P250F/320F Magazine 40 S&W/357 14 Round Md: MAG-MOD-F-43-14
Sig Sauer P250/P320 10 Round .40 S&W/.357 SIG Full Size Magazine
Sig Sauer MAGMODC4313 Magazine P250/P320 40 S&W/35
Sig Sauer MAG-P320-40/357 10RD Compact Magazine .357 SIG/.40 S&W Blued Steel
Sig Sauer P250/P320 Sub Compact 10 Round Magazine
Sig Sauer P320/P250 Full Size 9mm 17rd Magazine
Sig Sauer Magazine P250P320 9MM Luger Full Size 10-ROUNDS
Sig Sauer P320/P250 Compact 9mm Luger 15rd Blued Magazine
Sig Sauer P250/P320 Compact 9mm 10-Round Magazine
Sig Sauer P320/P250 Sub-Compact 9mm 12rd Magazine
Sig Sauer MAG-MOD-SC-380-12 .380 ACP 12-Round Black Steel Magazine
Sig Sauer P938 Micro Compact 9mm Luger 3" Barrel 7+1 Capacity Black
Sig Sauer MAG191199 9mm 9-Round Stainless Steel Magazine for 1911 Pistols
Sig SAUER 9mm 115gr Elite V-Crown JHP 20 Rounds/Box Ammo (E9MMA1-20)
Sig SAUER Elite Performance 40S&W 180Gr VCrown JHP
Sig Sauer E40SW220 40 S&W Jacketed Hollow Point 180 Grain 20 Rounds
Sig Sauer Elite V-Crown .45 ACP 185 gr JHP Ammo
Sig Sauer BBLMK25 P226 9mm Luger 4.40 Inch Chrome Lined Steel Barrel
Sig GUIDE-4 Recoil Spring Guide 228/229/250C
Sig Sauer MAG-229-9-15 9MM 15-Round Steel Magazine, Blued Finish
Sig Sauer BBL22919T P229 9mm 3.9" Black Nitride Threaded Barrel
Sig Sauer BBL9389T 9mm P938 Threaded Barrel 3.2" Black Nitride Steel
SigTac P227 45 ACP Magazine 10 Round Md: MAG-227-45-10
Sig Sauer MAG229910E2 9mm 10-Round Steel Magazine for P229-1 Pistols
Sig Sauer BBL9389 P938 9mm 3" Black Nitride Steel Replacement Barrel
Sig Sauer BBL2269 P226 9mm 4.4" Black Phosphate Barrel Chrome-Lined
Sig Sauer E40SW120 Elite Defense 40 S&W 165 gr JHP 20 Bx
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 322C-ROSE-RS P322 Rose 22 LR 4" Black Anodize Semi
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 W365XL-9-BXR3P-MS P365 XL 9mm 3.7" Nitron Semi-Aut
Sig Sauer 2401191R Picatinny Stock Adapter for AR-15, Alumin
Sig Sauer SORX1080 24MM Black Pro Optics Ready Sight
SIG SAUER E26R-9-BSS-FBZ P226 Full-Size 9mm 4.4" 2-Tone Bron
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