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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 (2,385)
Sinclair INTERNATIONAL TIN COATED EXPANDER MANDREL 270 CALIBER (0.276")
Sinclair International 6.5mm Tin Coated Expander Mandrel
Sinclair INTERNATIONAL TIN COATED EXPANDER MANDREL 25 CALIBER (0.256")
Sinclair INTERNATIONAL TIN COATED EXPANDER MANDREL 6MM (0.242")
Sinclair INTERNATIONAL TIN COATED EXPANDER MANDREL 20 CALIBER (0.203")
Sinclair INTERNATIONAL TIN COATED EXPANDER MANDREL 17 CALIBER (0.171")
Sinclair INTERNATIONAL 22-250 REMINGTON BULLET SEATING DIE
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 6.5X284 WINCHESTER (NORMA)
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 260 REMINGTON
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 243 WINCHESTER
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 338 LAPUA
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 300 WINCHESTER MAGNUM
Sinclair INTERNATIONAL MICRO-ADJUST BULLET SEATING DIE 6.5X47MM LAPUA
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 338 CALIBER (.337")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 8MM (.322")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 30 CALIBER (.307")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 7MM (.283")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 270 CALIBER (.276")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 6.5MM (.263")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 25 CALIBER (.256")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 6MM (.242")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 22 CALIBER (.223")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 20 CALIBER (.203")
Sinclair INTERNATIONAL CARBIDE EXPANDER MANDREL 17 CALIBER (.171")
Sinclair INTERNATIONAL SCOPE RING LAPPING TOOL 34MM
Sinclair INTERNATIONAL PICATINNY QD BIPOD ADAPTER
Sinclair INTERNATIONAL SHOOTING REST LEG ASSEMBLY 3 PACK
Sinclair INTERNATIONAL SHOOTING REST LEG ASSEMBLY
Sinclair INTERNATIONAL NO TOP HEAVY VARMINT AMBIDEXTROUS SHOOTING REST
Sinclair INTERNATIONAL BASIC TOP HEAVY VARMINT AMBIDEXTROUS SHOOTING REST
Sinclair INTERNATIONAL BENCHREST HEAVY VARMINT AMBIDEXTROUS SHOOTING REST
Sinclair INTERNATIONAL PRIMING HEAD TOOL BELTED MAG/WSM/ULTRA MAG
Sinclair INTERNATIONAL PRIMING HEAD TOOL 308 FAMILY/BR FAMILY
Sinclair INTERNATIONAL PRIMING HEAD TOOL PPC
Sinclair INTERNATIONAL PRIMING HEAD TOOL 223 FAMILY
Sinclair INTERNATIONAL SHOOTING REST SPEED SCREW 1/2"X20 THREADS
Sinclair INTERNATIONAL STUCK CASE REMOVER
Sinclair INTERNATIONAL CASE PREP CENTER ADAPTER
Sinclair INTERNATIONAL TRIMMER STAND ONLY
Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 50 CALIBER
Sinclair INTERNATIONAL NECK TURNING MANDREL SS 8MM (.321")
Sinclair INTERNATIONAL CROSS BOLT DIE LOCKING RING STAINLESS STEEL 3 PACK
Sinclair INTERNATIONAL DIE LOCK RING PLIERS FOR SINCLAIR
Sinclair INTERNATIONAL UNIVERSAL FLASH HOLE DEBURRING TOOL GEN 2 HANDLE ONLY
Sinclair INTERNATIONAL ALL-PURPOSE SHOOTING REST NON-WINDAGE REST TOP
Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 8MM (.322")
Sinclair INTERNATIONAL NECK TURNING CASE HOLDER #8 505 GIBBS
SINCLAIR INTERNATIONAL BULLET SORTING STAND WITHOUT INDICATOR
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 E26R-9-BSS-FBZ P226 Full-Size 9mm 4.4" 2-Tone Bron
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...
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Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
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