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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)
Sierra High Velocity Varminter Rifle Bullets .22 ca .224" 50 gr SPT 100-ct
Sierra 1310 Varminter .22 Cal .224 45 gr Spitzer 100 Per Box
Sierra 1210 Varminter .22 Cal .224 45gr Hornet Rifle Bullets 100ct
Sierra 1200 Varminter 22 Cal 40gr Round Nose Hornet Bullets 100/Box
Sierra 1110 Varminter 22Cal 45gr Round Nose Hornet 100/Box
Sierra 1100 Varminter 22 Cal 40gr Round Nose Hornet Bullets 100/Box
Sierra 1039 BlitzKing 20 Cal .204 39 gr 100 Per Box
Sierra 1036 .204 36Gr Tipped VarmintKing Precision
Sierra 1032 BlitzKing 20 Cal .204 32 gr 100 Per Box
Sierra 0600 Reloading Manual 6th Edition | 1368 Pages | Cartridge Info | Glossary | Q&A | Tools | Bore Care | Firearms Cleaning
Sierra 4610GT Tipped GameKing 30Cal 210gr 50/Box
Sierra MatchKing-X Rifle Bullets 6.5mm .264 142 gr HPBT 500/ct
Sinclair International Premium Uniformer Kit - Primer Pocket Edition
Sinclair Intl Bullet Sorting Stand w/Dial Indicator 050806111561 Universal
Sinclair International Hex Style Bullet Comparators - Unique Design, High Quality
Sinclair International Hex Style Bullet Comparators - Unique Design, High Quality
Sinclair International Bullet Comparator - Insert Style, Model 050806111530
Sinclair 050806111523 308 AR Cleaning Link
Sinclair International AR-15 Rod Guide, Link Kit by Sinclair
Sinclair International AR-15 Bolt Vise, High Quality, Durable
Sinclair 050806111400 Remington Firing Pin Removal Tool
Sinclair International Bullet Comparator - Insert Style, Model 050806111332
Sinclair International Bump Gage Insert - Unique 050806111325 Model
Sinclair International Bump Gage Insert - Unique 050806111318 Model
Sinclair INTERNATIONAL SHOULDER BUMP GAGE INSERT #40A 40 DEGREE 25-338/ACKLEY
Sinclair International Bump Gage Insert - High Quality, Precision Tool
Sinclair International Bump Gage Insert - High Quality, Precision Tool
Sinclair International Bump Gage Insert - High Quality Precision Tool
Sinclair INTERNATIONAL SHOULDER BUMP GAGE INSERT #45A 45 DEGREE WILDCATS
Sinclair INTERNATIONAL SHOULDER BUMP GAGE INSERT #20A 20 DEGREE 338 LAPUA
Sinclair International Bump Gage Insert for 243 Winchester, 260 Remington, 7mm-08 Remington, 7x64mm Brenne, 307 Winchester, 308 Marlin Express, 308 Winchester
Sinclair International Bump Gage Insert for AVV_25-06 Remington, BKK_270 Winchester, BNN_280 Remington, CMM_30-06 Springfield, CVV_7.62 x 39 mm
Sinclair INTERNATIONAL SHOULDER BUMP GAGE INSERT #35 35 DEGREE 30 NOSLER/284/WSM
Sinclair International Bump Gage Insert - Unique Precision Tool
Sinclair International #23 Bump Gage Insert 5.56 mm NATO Steel
Sinclair International Bump Gage Insert for Cartridge AII_22-250 Remington, ALL_223 WSSM, AQQ_243 WSSM
Sinclair International Bump Gage Insert Cartridge for AFF_220 Swift
Sinclair International Offset Scope Level - High Precision Instrument
Sinclair International Generation II Expander Dies - High Precision Tool
Sinclair Intl RT-3 Lightweight Benchrest Style Rest Complete
Sinclair International Arbor Press - High Quality, Durable Design
Sinclair International Bench Mount Scope Stand - Model 050806110939
Sinclair Ultimate Stainless Case Trimmer with Stand 050806110892
Sinclair 050806110878 Case Neck Wall Thickness Micrometer
Sinclair International 050806110861 Stainless Steel Priming Tool
Sinclair International 050806110823 Heavy Varmint Rest
Sinclair International AR-15/308 AR Lug Recess Cleaning Equipment
Sig SAUER, INC. P365-XMACRO TACOPS 9MM 3.7"BBL (4)17RD BLACK MULTI CAMO
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.
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
Sig Sauer P365 9mm 3.1 Inch NITRON Striker Fired Compact Han
Sig Sauer P226 X-Five Extreme Semi-automatic Single Action O
Sig Sauer P226 Magazine 10rd 40 S&W/357 SIG Stainless Steel
Sig Sauer WRMCX-556N-9B-LT-SBR MCX SBR 223 Rem | 5.56 NATO 9
Shop SI Products
Sig SAUER MCX-SPEAR 6.8x51mm SBR 13in Semi-Auto Rifle RSPEAR
Sig Sauer P320 FLUX 9MM 3.9" 30RD Legion 320
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
Sierra 1502 BlitzKing Rifle Bullets 6mm .243 55gr 100ct
Sierra MatchKing-X Rifle Bullets .30 Cal 175 gr HPBT 500/ct
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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