SKU: SG1811268-R
UPC: 798681608560
MPN: 1811268-R
The SIG Sauer Taper Cap PCC is a muzzle adapter built to solve a specific problem on SIG's pistol caliber carbines: the factory tapered barrel shoulder won't index standard muzzle devices the way a flat shoulder does. This cap threads onto the tapered muzzle and presents a conventional 90-degree shoulder, opening the door to a wide range of brakes, flash hiders, and suppressor mounts. It's aimed at owners running SIG PCC, MPX, and MCX platforms who want to step outside the factory muzzle hardware. Carrying MPN 1811268-R, it's a small part that changes what you can hang off the end of the barrel.
Construction is steel with a black coating, which holds up to the heat and pressure at the muzzle better than aluminum would. The thread spec is 1/2x28 right-hand, the standard pitch for most 9mm and pistol-caliber muzzle devices, so it pairs with the bulk of aftermarket brakes, compensators, and direct-thread suppressor adapters on the market. The function is straightforward: the cap seats against the tapered barrel and gives you a true square shoulder to torque a muzzle device against, ensuring proper indexing and a consistent crush washer or shim stack. Without this conversion, a tapered SIG muzzle limits you to SIG's own proprietary devices. If you're sorting through other muzzle and barrel hardware, our broader parts catalog covers the supporting pieces.
Reach for this taper cap when you've decided on a specific brake, flash hider, or suppressor mount that uses standard 1/2x28 threads and your SIG carbine came with a tapered muzzle. It's the bridge between SIG's barrel geometry and the rest of the muzzle device market, and it earns its place on builds where the factory hardware doesn't fit the plan. Pair it with a thread protector or your chosen muzzle device for a finished setup. Shooters working on PCC builds often pick up related barrel components and accessories and dedicated PCC trigger hardware at the same time.
It threads onto SIG's tapered barrel muzzle and presents a standard 90-degree shoulder. This lets you mount conventional muzzle devices, brakes, flash hiders, and suppressor adapters that need a flat shoulder to index against, rather than being limited to SIG's proprietary tapered-shoulder hardware.
The cap is cut for 1/2x28 right-hand threads, the common pitch for 9mm and pistol-caliber muzzle devices. That makes it compatible with the majority of aftermarket brakes, compensators, and direct-thread suppressor mounts built for that thread.
It fits SIG PCC, MPX, and MCX models that ship with a tapered barrel shoulder. If your carbine already has a standard flat shoulder and 1/2x28 threads, you won't need this adapter. Confirm your barrel's muzzle geometry before ordering.
It's built from steel with a black coating. Steel handles the heat and torque at the muzzle better than aluminum, which matters since the cap takes the load when you crush-washer or shim a muzzle device against its shoulder.
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