Silencer Definition Expanded: PARTS Act Includes Outer Tubes and Housings Under Federal Law

The PARTS Act of 2025 proposes a significant update to federal law by changing the definition of "firearm silencer" and "firearm muffler." Currently outlined in title 18, section 921(a)(25) of the United States Code, the existing definition focuses on complete devices. This bill expands that definition to explicitly include not just fully assembled silencers, but also specific key components: namely, the outer tube or any single part that serves as the primary housing for the internal sound-reducing elements, provided it's designed and intended for silencing and attaches to a firearm.

Redrawing the Lines: What's Now Considered a Silencer?

This legislative change fundamentally alters what falls under the legal category of a silencer. Previously, regulations primarily targeted finished products. Under Section 2 of the PARTS Act, certain individual parts – specifically the main external body or housing – could potentially be treated legally like a complete silencer if they meet the criteria of being designed, made, and intended for sound suppression and attachment to a firearm. This means manufacturers, sellers, and potentially buyers of these specific components might face different regulatory requirements than they do currently. For instance, purchasing just the outer tube of a silencer could, under this definition, be viewed differently than buying unregulated metal tubing, depending on its design and intended use.

Downrange Differences: Potential Impacts on Owners and Safety

The practical effects of this redefinition could ripple outwards. On one hand, proponents might argue this clarifies the law around components. Shooters often use silencers for hearing protection and reducing noise pollution at ranges. On the other hand, broadening the definition to include parts raises questions about oversight and public safety. If key components are regulated differently or become easier to obtain separately, it could potentially complicate tracking and control efforts for law enforcement, as noted in the analysis identifying potential concerns around Oversight Reduction and Protection Removal linked to Section 2. The interpretation of terms like "intended to silence" and how existing regulations adapt to this parts-inclusive definition remain areas to watch, contributing to a medium level of vagueness regarding the bill's real-world application.