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"Innovative firearm accessories engineered for performance"

SI designs rugged, user-focused firearm components and optics. They make accessories like slide plates, charging handles, barrel clamps, red dots, and shotgun parts.

5.0★★★★★(82 verified SI reviews)

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7,545

Products

2,386

In Stock

Founded

USA

Origin

All SI Products (2,386)

Sinclair INTERNATIONAL MODEL 1000 SHOOTING REST BASIC TOP

Sinclair INTERNATIONAL BENCH BLOCK FOR REMINGTON BOLTS

Sinclair INTERNATIONAL CARBIDE 28 DEGREE CUTTER

Sinclair INTERNATIONAL BENCHREST C-FRAME RELOADING PRESS MOUNTING PLATE

Sinclair INTERNATIONAL CASE MOUTH DEBURRING TOOL HOLDER

Sinclair INTERNATIONAL SHOOTING REST POST 4" STAINLESS STEEL

Sinclair INTERNATIONAL NECK TURNING CASE HOLDER #2 PPC FAMILY

Sinclair International Case Holder 220 Swift Precision

Sinclair INTERNATIONAL BRASS CASE BRITE MEDIA TREATED CORN COB 5 POUNDS

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 50 CALIBER (.508")

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 50 CALIBER (.509")

Sinclair INTERNATIONAL TRIMMER SPACER

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 416 CALIBER (.414")

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 9.3MM (.364")

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 35 CALIBER (.356")

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 416 CALIBER(.415")

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 375 CALIBER(.374")

SINCLAIR INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 9.3MM (.365")

Sinclair INTERNATIONAL REPLACEMENT NECK TURNING CUTTER 40 DEGREE

Sinclair INTERNATIONAL REPLACEMENT NECK TURNING CUTTER 30 DEGREE

Sinclair INTERNATIONAL PRIMER POCKET UNIFORMER HANDLE 8000 SERIES

Sinclair INTERNATIONAL BIPOD ADAPTER STANDARD RAIL

Sinclair INTERNATIONAL ARBOR DIE SHIM KIT 22 CALIBER TO 6MM

Sinclair INTERNATIONAL ARBOR DIE SHIM KIT 25 TO 30 CALIBER

Sinclair INTERNATIONAL FLASH HOLE TOOL ONLY

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 20 CALIBER (.202")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 20 CALIBER (.203")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 270 CALIBER (.275")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 25 CALIBER (.255")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 25 CALIBER (.256")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 338 CALIBER (.337")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 17 CALIBER (.170")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 17 CALIBER (.171")

Sinclair INTERNATIONAL BRENCHREST PRACTICE TARGETS 25 PACK

Sinclair INTERNATIONAL RPM BENCH MAT 16"X20"

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 30 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 7MM

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 6.5MM

Sinclair International Pilot Stop Stainless Steel 6mm

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 25 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 270 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 375 CALIBER

Sinclair INTERNATIONAL BULLET SEATING DEPTH GUIDE 0.690" DIAMETER

Sinclair International Priming Tool Shell Holder #19, Stainless, 9mm/40 S&W

Sinclair INTERNATIONAL ROD GUIDE INSERT 22 CALIBER

Sinclair INTERNATIONAL CLEANING ROD WALL BRACKET

Sinclair INTERNATIONAL NYLON PISTOL BORE BRUSH 44/45 CALIBER 8-32M 12 PACK

Sinclair Nylon Rifle Bore Brush 30 Caliber 12 Pack

About SI

SI focuses on practical, performance-driven firearm accessories for a wide range of pistols, rifles, and shotguns. Their lineup includes slide adapter plates, latchless charging handles, barrel clamps, compact red dot optics, and dedicated shotgun components, built primarily from aluminum and hardened materials. Products are engineered with attention to fit, function, and ease of installation, aimed at shooters who want reliable upgrades without unnecessary complexity. SI supports competitive, tactical, and recreational shooters by offering parts that address common user needs and enhance firearm ergonomics and capability.

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.