1/2×28 Adapter for EFK Five-seveN Threaded Barrel Overview
The 1/2×28 adapter enhances your FN Five-seveN by converting EFK Fire Dragon barrel threads from 10×1 mm to the common 1/2×28 standard. Each new EFK barrel already includes this adapter—making this product ideal as a backup or replacement.
Key Features
- 10×1 mm to 1/2×28 conversion — allows EFK Five-seveN barrels to use common muzzle devices.
- Concentric interface — supports proper bore alignment when installed correctly.
- Secure thread engagement — designed for repeatable fit and reliable use.
- Five-seveN focused — purpose-made for EFK Fire Dragon threaded barrels.
Compatibility
- Designed for: EFK Fire Dragon threaded barrels for FN Five-seveN (IOM, USG, MK2, MRD/MK3).
- Not for: factory non-threaded barrels or non-EFK thread patterns.
Installation
Thread the adapter fully onto the 10×1 mm barrel, verify shoulder contact, then install your 1/2×28 device. Always verify concentricity before use.
Why FN Specialties
FN-focused expertise, authenticity guaranteed, and compliance-aware guidance for the Five-seveN platform.
Related Enhancements
- EFK Fire Dragon Threaded Barrel for Five-seveN — threaded barrel foundation for this adapter.
- Five-seveN Accessories — explore optics, sights, and platform enhancements.
FAQs
Does this adapter come with new EFK barrels?
Yes. Each new EFK Fire Dragon barrel includes one adapter. This listing is for an additional or backup unit.
Will this fit MRD/MK3 models?
Yes—if your Five-seveN uses an EFK Fire Dragon threaded barrel.
Is NFA paperwork required?
No. This adapter does not change the firearm’s classification.
Compliance
- Verify state and local laws before purchase and installation.
