California does not publish a simple, fixed “list” of precursor parts. Instead, the law defines them broadly—and that puts the burden on FFLs to interpret and classify correctly.
What Is a “Firearm Precursor Part”?
Under California law (SB-704), a precursor part is generally:
A component that can be used to build or convert a firearm and is determined to be critical to its function.
Key Point for FFLs
This is intentionally broad. It’s not a checklist—it’s a category.
Commonly Regulated Precursor Parts (Practical Examples)
While not exhaustive, FFLs should closely scrutinize:
- Frames and receivers (including unfinished variants)
- Fire control components
- Certain upper/lower assemblies
- Parts kits that could be used to build a firearm
What Is NOT Typically Included
(Not guaranteed—classification matters)
- Cosmetic parts (grips, stocks, etc.)
- Accessories (optics, lights, slings)
- Non-critical hardware
Why There’s No Clear List
California structured the law this way to:
- Prevent workarounds
- Allow regulators to expand interpretation over time
👉 Translation for FFLs: If you’re waiting for a “safe list,” it doesn’t exist.
FFL Risk: Misclassification
The biggest compliance risk is:
- Treating a regulated part like a normal retail item
- Failing to route it through proper transfer procedures
Best Practice for Dealers
- Default to caution on borderline items
- Verify whether a part could be considered “critical to function”
- Document your classification decisions
FFL-Only CTA
If you’re an FFL trying to determine whether a part qualifies as a precursor part:
👉 FFL+ provides clear, dealer-focused guidance so you don’t have to guess.