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 (2,363)
Simmons SPH842 ProHunter 8x42mm Matte Binoculars
Simmons Spotting Scope 20-60X60 Tripod Hard/Soft Case
Simmons Venture 10x42mm Binoculars Roof Prism Black 8971042R
Simmons Venture Spotting Scope 15-45x60mm Straight Black SP154560B
Simmons ProTarget Matte Black 6-24x 44mm 30mm Tube Mil-Dot Reticle
Simmons ProTarget SIM41640 4-16x40mm 30mm Mil-Dot Reticle Matte Black
Simmons SIM41240C ProTarget Black 4-12x 40mm Rifle Scope
Simmons ProTarget SIM3940C 3-9x40mm Rifle Scope Black
Sinclair 00252882 Double Headed Cotton Swabs 100 Pack
Sinclair H-4W Hook and Pick Set, Durable Steel Construction
Sig Sauer P365 Handgun Magazine 9mm Luger 10/rd Bulk
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 August 2026
Trending right now based on the last 30 days of TheGunDock orders + page views.
Sig Sauer Defensive Rifle Ammo 300 Blackout 194 gr. Max Expa
Sig Sauer WPMPX-8B-9-35 MPX K 9mm 8" Black Semi-Auto Pistol
Sig Sauer BuckMaster 3-12x44 Rifle Scope Hellfire BDC Reticl
Sig Sauer P322 Rose 22 LR 4 In 20-Rd (3 Mags) Black w/ ROMEO
Limbsaver 10801 AirTech Recoil Pad Mossberg 500C/Marlin 308M
Sig Sauer W365XCA-9-COMP P365 X-Macro 9mm 3.1" Nitron Semi-A
Sig SAUER, INC. P365-XMACRO TACOPS 9MM 3.7" BBL (4)17RD WHIT
Sig Sauer P365X Semi-automatic Striker Fired Polymer Frame P
Shop SI Products
Sig Sauer P322 Rose 22 LR 4 In 20-Rd (3 Mags) Black w/ ROMEO
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
SIG SAUER RMPX-4B-9-35-SBR MPX SBR 9mm 4.5" Black NFA - Shor
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
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