PiggyFoam Underbarrel Masterkey | Hardware Kit

The Underbarrel Masterkey by Shellington Labs is a compact, spring-powered shotgun platform designed to mount directly beneath your primary blaster via standard Picatinny rail systems. Built to deliver a reliable and satisfying secondary firing option, the Masterkey adds close-range versatility without sacrificing maneuverability or balance. Its streamlined form factor makes it an ideal underbarrel companion for competitive play, scenario games, or loadouts that demand flexibility.

Inspired by classic underbarrel launchers such as the M203 and GP-25, the Masterkey blends iconic military styling with modern foam-blaster engineering. Feeding from Silly Shells, it supports a wide range of ammunition types while delivering approximately 80% of the power of a Spring Thunder in a far more space-efficient package. As a hardware kit, it’s perfect for builders looking to integrate a functional, tactical shotgun into their existing platforms.

Product Note: This listing is for the hardware kit only. 3D printed parts, shells, and mounting accessories are sold separately.

Features:

• Spring-powered, Silly Shell–fed shotgun platform
• Designed for under-barrel mounting via standard Picatinny rail systems
• Provides an effective secondary / backup firing option for most foam blasters
• Inspired by classic underbarrel launchers such as the M203 and GP-25
• Space-efficient design delivering approximately 80% of Spring Thunder performance
• Ideal for tactical builds, modular loadouts, and close-range engagements

Product Resources:

• 3D Files
• Video Assembly Instructions
• Silly Shells

Included:

• Underbarrel Masterkey Hardware Kit ONLY
• PiggyFoam K25 Spring
• Lube

Licensed Retailer: Ideal Foam Blaster (IFB) is an authorized retailer for PiggyFoam.