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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 (2,390)
Sierra A466906 GameChanger 30-06 Springfield 165 gr Tipped GameKing 20 Rds
Sierra A444003 GameChanger .270 Win 140 gr Tipped GameKing 20 Rounds
Sierra GameChanger 6.5 Creedmoor 130 Grain Brass Cased Ammo 20 Rounds
Sierra A410302 GameChanger 243 Win 90 gr 3200 fps Tipped GameKing 20 Bx/10 Cs
Sinclair 608060400565 50 Caliber Nylon Rifle Brushes 12-Pack
Sinclair 608060400558 45 Cal 8-32M Bronze Brushes 12-Pack
Sinclair 608060400541 45 Caliber Nylon Rifle Brushes 12-Pack
Sinclair 608060400527 41 Caliber Nylon Rifle Brushes 12 Pack
Sinclair 608060400411 270-284 Cal 8-32M Bronze Brushes 12-Pack
Sinclair 608060400305 20 Caliber Bronze Rifle Brushes 12 Pack
Sinclair 608060400251 37 Cal Nylon Rifle Brushes 12-Pack
Sinclair 608060400244 10mm/40 Cal Nylon Pistol Brushes, 12 Pack
Sinclair 608060400213 338 Caliber Nylon Rifle Brushes 12-Pack
Sinclair 608060400206 22 Caliber Nylon Pistol Brushes 12-Pack
Sinclair 608060400152 6.5mm 25 Cal Nylon Rifle Brushes 12-Pack
Sinclair 608060400145 6mm Nylon Rifle Brushes 12-Pack
Sinclair 608060400121 22 Caliber Nylon Rifle Brushes 12-Pack
BlackPoint Tactical P365XL Holster, Right-Hand Draw, Composite Material, 1.50in Belt Loop, IWB Appendix Carry
Sig SAUER P365 Left Hand OWB Holster, Optic Ready, 1.5-1.75in Belt Loop, Composite, Black, Medium
BlackPoint Tactical P365 OWB Holster - Composite Material, Ideal Concealment, Belt Loop Sizes 1.5in & 1.75in, Left Hand Use
Sig Sauer P365XL OWB Holster Right Hand Kydex Black 1.5in 1.75in Loop
Sig Sauer P365 XL Left Hand IWB Holster Kydex Black Adjustable Ride
Sig Sauer P365 Handgun Grip 9mm Luger/380 Manual Safety Black Bulk
Sierra 9240 MatchKing .30 Cal .308 210gr HPBT Bullets 500ct
Sierra MatchKing Rifle Bullets .25 Cal .257 131 gr HPBT/CN 250/ct
Sierra 9377MP MatchKing 22Cal 77gr HPBT Bullets 250/Box
Sierra MatchKing Rifle Bullets .30 cal .308 177 gr HPBT/CN 250/ct
Sierra 2269MP MatchKing 30Cal 169gr Hollow Point Boat Tail 250/Box
Sierra MatchKing Rifle Bullets 6.5mm .264 142 gr HPBT/CN 250/ct
Sierra 1575MP MatchKing 6mm 110gr HPBT 250/Box
Sierra 1570MP MatchKing 6mm 107gr HPBT 250/Box
Sierra Bullets 9377G 22 Cal 77gr HPBT Cannelure 500/Box
Sierra Green Tipped GameKing Rifle Bullets .30 cal .308 210 gr TGK 500/ct
Sierra A468106 30-06 Ammo 180GR TGK 20 Rounds 2760 FPS
Sierra A937709F 223 REM 77GR HP BT Ammo, 20 Rounds, Folds of Honor Edition
Sierra A2140-06 .30-06 Sprg 165gr HPBT Rifle Ammo 20 Rounds
Sierra A8460 Outdoor Master 40 S&W 180gr JHP Ammo 20 Rounds
Sierra A8800 Outdoor Master 45 ACP 185GR JHP Ammo 20 Rounds
Sierra A8124--20 Outdoor Master 9mm 124GR JHP Ammo 20RD Box
Sierra MatchKing Rifle Bullets .25 Cal .257 131 gr HPBT/CN 500/ct
Sierra 9362 High Velocity GameKing Rifle Bullets .22 Cal 62gr SBT 500ct
Sports Master 9MM (.355") Jacketed Hollow Point Handgun Bullets 8124C
Sierra 7795C 30 Caliber (.308) 195gr Tipped MatchKing Bullets 500/Box
Sierra Tipped MatchKing .30 Caliber 175 Grain TMK 500 Rounds
Sierra 7768C Tipped MatchKing .30 Caliber 168 Grain Bullet 500 Count
30Cal 155Gr TMKMAT Rifle Bullets - 500 Count Box
Sierra 7725C .30 Caliber 125 Grain Bullet 500 Count Tipped MatchKing
Sierra 7660C Tipped MatchKing Rifle Bullets .284 Cal 160gr 500ct
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...
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