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 (2,381)
SilencerCo ASR Active Spring Retention Mount Quick Attach/Detach System
SilencerCo 3-Lug Muzzle Device 5/8x24 9mm Black
SilencerCo AC2608 3-Lug Muzzle Device M13.5x1LH Threads 45 ACP
SilencerCo 3-Lug Muzzle Device 1/2x36 9mm Black
SilencerCo 3-Lug Muzzle Device .578x28 .45 ACP Black
SilencerCo AC2602 3-Lug Muzzle Device M13.5x1LH Threads 9mm
SilencerCo 3-Lug Muzzle Device 45 ACP 5/8-24 Black
SilencerCo Threaded Barrel For Sig P320 Compact 9m
SilencerCo AC2413 9mm Threaded Barrel 5.46" Black Nitride Stainless Steel
SilencerCo 3-Lug Mount .45 Cal AC2448
SilencerCo 3-Lug Mount for Silencer Co Octane, Omega K, and Hybrid - Stainless Steel, Black Oxide Finish
SilencerCo AC2291 9mm Threaded Barrel 5.30" Black Nitride Stainless Steel
SilencerCo AC2290 9mm Threaded Barrel 3.50" Black Nitride Stainless Steel
SilencerCo AC2024 Threaded Barrel 5.10" 45 ACP Black Nitride Steel
SilencerCo AC2023 Threaded Barrel 9mm Luger 4.9 in Black Nitride
Silencerco Bravo Anchor Brake .30 Caliber Recoil Reduction Grey
SilencerCo AC1986 Suppressor Cover 7.5in FDE - Cordura Nylon Exterior, New Condition
SilencerCo AC1985 High Temp Suppressor Shield FDE 6 Inch
SilencerCo High Temp Suppressor Cover 7.50" Compatible with Octane Saker...
SilencerCo AC1983 High Temp 6" Suppressor Cover - Black, 1600°F Heat Shield
SilencerCo 7.5" High Temp Suppressor Shield Grey AC1982
SilencerCo AC1981 High Temp 6" Gray Suppressor Cover Nylon
SILENCERCO ASR .46 Caliber 11/16x24 Muzzle Brake (AC1961)
SilencerCo Hybrid ASR Muzzle Brake .458 Caliber Black
SilencerCo AC1570 Hybrid ASR Muzzle Device 9mm
Sightmark SM1804101 Wraith Mini Long Mount Black Aluminum Matte Finish
Sightmark SM13142LR2 Presidio 5-30x56 30mm Scope Matte Black Illuminated
Sightmark SM13141LR2 Presidio 3-18x50 30mm Scope Matte Black LR2 Reticle
Sightmark SM13140CR1 Presidio 1-6x24 30mm Scope Matte Black Illuminated
Sightmark SM28004 Mini QD Battery Pack, Lithium-Polymer, Matte Black
Sightmark Wraith 4K 1x Monocular - High-Definition Night Vision
Sightmark Mini Shot M-Spec M3 Solar Red Dot Sight 3 MOA IP67 Waterproof
Sightmark SM26033R 33X24MM Reflex Sight Optics Ready
Sightmark SM39047 6.5 Grendel Red Laser Boresight, Brass, 100-Yard Range
Sightmark Mini Shot A-Spec M3 Micro Reflex Sight 1x33mm Black
Sightmark SM26041 Element Mini Solar Red Dot Sight 1x22mm 3 MOA Black
Sightmark 26030 Volta Red Dot 1x28mm 2 MOA Solar/AAA Matte Black
Sightmark SM26045 Mini Shot A-Spec M1 Red Dot 2 MOA Matte Black 1x22x17mm
Sightmark SM13138HDR Citadel 1-10x24 HDR Riflescope
Sightmark LoPro Mini Green Laser Sight - Flat Dark Earth
SIGHTMARK LOPRO Flashlight & IR Green Laser Dark E
Sightmark SM25012DE LoPro Mini Combo Flashlight & Green Laser 300 Lumens
Sightmark T-5 5x23mm Magnifier w/ LQD Flip Mount
Sightmark T-3 Magnifier 3x Red Dot Reflex Sight Co-Witness Mount
Sightmark SM26018 Core Shot A-Spec Reflex Sight 5 MOA Red Dot Matte Black
Sightmark SM26017 Core Shot A-Spec FMS Reflex Sight Matte Black 1 x 28 ...
Sightmark SM34022 Tactical 34mm Fixed Cantilever Scope Mount-Ring Combo ...
Sightmark SM34019 Tactical 30mm Cantilever Scope Mount Matte Black
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 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...
Ready to Shop SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
Browse All Products