This Sig Sauer piston (Sig Sauer part no. 4204140-R) is an extended, long-stroke design built specifically for the MCX Spear’s gas system.

Key Specifications

• Brand: Sig Sauer.
• Product type: gas piston.
• Length: extended (vs. factory-length piston).
• Piston type: long-stroke design.
• Fits: Sig MCX Spear.

Frequently Asked Questions

What platform is this piston built for? The Sig Sauer MCX Spear’s gas system specifically.

What’s the difference between this and the factory piston? This version is extended-length with a long-stroke design, as opposed to a factory short-stroke piston.

Buy the Sig Sauer Extended Long-Stroke Piston, MCX Spear

Get the Sig Sauer Extended Long-Stroke Piston, MCX Spear from Sig Sauer, browsable in our full Other Gun Accessories & Parts selection. Our Lubbock, Texas team ships fast, insured orders every day.