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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
2,387
In Stock
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Founded
USA
Origin

All SI Products (2,387)

Buy Sierra Bullets 1742C 6.5mm 142gr HPBT MatchKing 500/Box online Sierra Bullets 1742C 6.5mm 142gr HPBT MatchKing 500/Box Buy Sierra 1740C MatchKing Rifle Bullets 6.5mm/.264 140gr HPBT 500ct online Sierra 1740C MatchKing Rifle Bullets 6.5mm/.264 140gr HPBT 500ct Buy Sierra Bullets 1729C 6.5mm 130gr Hollow Point BT 500/Box online Sierra Bullets 1729C 6.5mm 130gr Hollow Point BT 500/Box Buy Sierra Bullets 1727C 6.5mm 123gr HPBT 500/Box online Sierra Bullets 1727C 6.5mm 123gr HPBT 500/Box Buy Sierra 1725C 6.5mm 120gr HPBT MatchKing Bullets 500/Box online Sierra 1725C 6.5mm 120gr HPBT MatchKing Bullets 500/Box Buy Sierra 1605C 25 Caliber 70GR Flat Base Bullets 500/Box online Sierra 1605C 25 Caliber 70GR Flat Base Bullets 500/Box Buy Sierra 1575C MatchKing 6mm 110gr Hollow Point Boat Tail 500/Box online Sierra 1575C MatchKing 6mm 110gr Hollow Point Boat Tail 500/Box Buy Sierra Bullets 1570C 6mm 0.243 in 107 gr HPBT 500 per Box online Sierra Bullets 1570C 6mm 0.243 in 107 gr HPBT 500 per Box Buy Sierra 1537C MatchKing 6mm/.243 95gr HPBT Rifle Bullets (500 Count) online Sierra 1537C MatchKing 6mm/.243 95gr HPBT Rifle Bullets (500 Count) Buy Sierra 1507C BlitzKing 6mm .243 70gr Rifle Bullets 500ct online Sierra 1507C BlitzKing 6mm .243 70gr Rifle Bullets 500ct Buy Sierra Bullets 1505C 6mm 70gr HPBT 500/Box online Sierra Bullets 1505C 6mm 70gr HPBT 500/Box Buy Sierra 1502C BlitzKing Rifle Bullets 6mm .243 55gr 500ct online Sierra 1502C BlitzKing Rifle Bullets 6mm .243 55gr 500ct Buy Sierra BlitzKing .22 Caliber .224 55 Grain Rifle Bullets 500 Count online Sierra BlitzKing .22 Caliber .224 55 Grain Rifle Bullets 500 Count Buy Sierra 1440C BlitzKing .22 Cal .224 40gr Rifle Bullets 500ct online Sierra 1440C BlitzKing .22 Cal .224 40gr Rifle Bullets 500ct Buy Sierra MatchKing 1410C .22 Caliber 52 Grain HPBT Match 500 Count online Sierra MatchKing 1410C .22 Caliber 52 Grain HPBT Match 500 Count Buy Sierra Bullets 1400C 22 Cal 53gr Hollow Point 500/Box online Sierra Bullets 1400C 22 Cal 53gr Hollow Point 500/Box Buy Sierra Bullets 1396C 22 Cal 95gr HPBT MatchKing 500/Box online Sierra Bullets 1396C 22 Cal 95gr HPBT MatchKing 500/Box Buy Sierra MatchKing Bullets (500/ct) .22 cal .224 69 gr HPBT MATCH - Designed for Service Rifle competition in the M16A2/AR-15A2. online Sierra MatchKing Bullets (500/ct) .22 cal .224 69 gr HPBT MATCH - Designed for Service Rifle competition in the M16A2/AR-15A2. Buy Sierra Bullets 1039C 20 Cal 39gr Boat Tail BlitzKing 500/Box online Sierra Bullets 1039C 20 Cal 39gr Boat Tail BlitzKing 500/Box Buy Sierra Bullets 1032C 20 Cal 32GR Flat Base BlitzKing 500/Box online Sierra Bullets 1032C 20 Cal 32GR Flat Base BlitzKing 500/Box Buy Sierra MatchKing Bullet .22 Cal 77gr HPBT Cannelured online Sierra MatchKing Bullet .22 Cal 77gr HPBT Cannelured Buy Sierra 9390T MatchKing 22 Cal 80GR HPBT Bullets 50/Box online Sierra 9390T MatchKing 22 Cal 80GR HPBT Bullets 50/Box Buy Sierra 9377T MatchKing 22Cal 77gr HPBT Bullets 50/Box online Sierra 9377T MatchKing 22Cal 77gr HPBT Bullets 50/Box Buy Sierra Bullets 9350T 375 Cal 350gr HPBT Rifle Bullets 50/Box online Sierra Bullets 9350T 375 Cal 350gr HPBT Rifle Bullets 50/Box Buy Sierra 9300T MatchKing 338 Cal .338 300 gr HPBT 50 Per Box online Sierra 9300T MatchKing 338 Cal .338 300 gr HPBT 50 Per Box Buy Sierra 9290T MatchKing 22Cal 90GR HPBT Bullets 50/Box online Sierra 9290T MatchKing 22Cal 90GR HPBT Bullets 50/Box Buy Sierra 9240T .30 Cal .308 210GR HPBT MatchKing Bullets 50ct online Sierra 9240T .30 Cal .308 210GR HPBT MatchKing Bullets 50ct Buy Sierra 4681T Green Tipped GameKing .30 Cal 180gr Bullets 50ct online Sierra 4681T Green Tipped GameKing .30 Cal 180gr Bullets 50ct Buy Sierra 4665T Tipped GameKing 308 Caliber 165 GR 50 Per Box online Sierra 4665T Tipped GameKing 308 Caliber 165 GR 50 Per Box Buy Sierra 4610GT Green Tipped GameKing .30 Cal 210gr Bullets, 50/Box online Sierra 4610GT Green Tipped GameKing .30 Cal 210gr Bullets, 50/Box Buy Sierra 4565T 7mm .284 165gr HPBT GameKing Expansion online Sierra 4565T 7mm .284 165gr HPBT GameKing Expansion Buy Sierra 4440T Tipped GameKing 270 Win 140 gr Hollow Point Boat Tail online Sierra 4440T Tipped GameKing 270 Win 140 gr Hollow Point Boat Tail Buy Sierra 4330T Tipped GameKing 6.5 Creedmoor .264 130 gr Hollow Point Boat-Tail (HPBT) 50 Per Box online Sierra 4330T Tipped GameKing 6.5 Creedmoor .264 130 gr Hollow Point Boat-Tail (HPBT) 50 Per Box Buy Sierra 4100T Tipped GameKing 6mm .243 90gr HPBT 50/Box online Sierra 4100T Tipped GameKing 6mm .243 90gr HPBT 50/Box Buy Sierra 2237 MatchKing 30Cal 215gr Hollow Point Boat Tail 50/Box online Sierra 2237 MatchKing 30Cal 215gr Hollow Point Boat Tail 50/Box Buy Sierra V-Crown 9mm Luger 90gr JHP Bullets - 100 Count online Sierra V-Crown 9mm Luger 90gr JHP Bullets - 100 Count Buy Sierra Bullets 9947 9mm 147gr JHP V-Crown Pistol Bullets, 100 Count online Sierra Bullets 9947 9mm 147gr JHP V-Crown Pistol Bullets, 100 Count Buy Sierra V-Crown 9mm Luger JHP 125gr Pistol Bullets - 100 Count online Sierra V-Crown 9mm Luger JHP 125gr Pistol Bullets - 100 Count Buy Sierra V-Crown 9mm Luger 124 gr. JHP Bullets - Ultimate Defense Line online Sierra V-Crown 9mm Luger 124 gr. JHP Bullets - Ultimate Defense Line Buy Sierra Bullets 9820 .45 Cal 200GR JHP V-Crown 100CT online Sierra Bullets 9820 .45 Cal 200GR JHP V-Crown 100CT Buy Sierra MatchKing Rifle Bullets .25 Cal .257 131 gr HPBT/CN 100/ct online Sierra MatchKing Rifle Bullets .25 Cal .257 131 gr HPBT/CN 100/ct Buy Sierra Bullets V-Crown 9465 10mm 165gr JHP 100 Count Box online Sierra Bullets V-Crown 9465 10mm 165gr JHP 100 Count Box Buy Sierra 9390 .22 Cal 80gr HPBT Bullets, 500/Box online Sierra 9390 .22 Cal 80gr HPBT Bullets, 500/Box Buy SIERRA BULLETS .22 CAL .224 77GR HPBT MATCHKING-X online SIERRA BULLETS .22 CAL .224 77GR HPBT MATCHKING-X Buy Sierra 9377 .22 Caliber 77 Grain HPBT Bullet 0.224 in 500 Count online Sierra 9377 .22 Caliber 77 Grain HPBT Bullet 0.224 in 500 Count Buy Sierra GameKing .22 Caliber 62 Grain Spitzer Boat Tail Hunting Bullets online Sierra GameKing .22 Caliber 62 Grain Spitzer Boat Tail Hunting Bullets Buy Sierra 9300 .338 Cal 300gr HPBT Bullets, 500/Box online Sierra 9300 .338 Cal 300gr HPBT Bullets, 500/Box Buy Sierra 9290 MatchKing 22Cal 90gr HPBT 500/Box online Sierra 9290 MatchKing 22Cal 90gr HPBT 500/Box

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.

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.

Ready to Shop SI?

Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....

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