FRT-15L3™ (FLAT)
Video review
Expert review
About this product
The FRT-15L3™ (FLAT) is a single-stage forced reset trigger for AR-15 platforms engineered to provide rapid, controlled fire through mechanical reset rather than traditional spring tension. This 3-position trigger system represents the third-generation evolution of FRT Triggers' proprietary forced-reset mechanism, with specific geometric optimizations for flat-faced trigger preference. The system operates through a precision-machined selector drum that engages the hammer hook geometry at precisely 0.85mm clearance.
What is the FRT-15L3™ (FLAT) used for?
The FRT-15L3™ (FLAT) is engineered for rapid, controlled fire in recreational and competitive shooting applications requiring minimal trigger reset distance. The forced-reset mechanism eliminates the traditional spring-based reset, allowing the shooter to maintain trigger contact while the system mechanically returns the trigger to the fire position after each shot. This design provides a consistent 3.1mm reset distance compared to the 9mm reset typical of mil-spec triggers. The flat trigger face optimizes finger placement for reduced perceived weight and improved control during rapid sequences.
How does the FRT-15L3™ (FLAT) compare to the Geissele SSA-E?
The FRT-15L3™ (FLAT) provides mechanical forced reset while the Geissele SSA-E relies on traditional spring-based reset mechanisms. The FRT system achieves a 68% shorter reset distance (3.1mm vs 9.8mm) but requires more precise lower receiver tolerances, specifically within the 0.85mm hammer pin-to-trigger housing clearance specified in our AR-15 Lower Receiver Machining Tolerance guide. The Geissele SSA-E offers superior compatibility across a wider range of lower receivers but cannot achieve the same rate of fire potential.
What does it weigh and what are the dimensions?
The FRT-15L3™ (FLAT) trigger assembly weighs 142 grams complete with anti-walk pins installed. The trigger shoe measures 12.7mm wide by 76.2mm long with a flat face geometry optimized for consistent finger placement. The entire drop-in unit requires a minimum clearance of 35mm x 25mm within the lower receiver fire control group pocket. The anti-walk pins are hardened steel with a diameter of 6.35mm and length of 44.5mm.
Who is this NOT for?
This trigger is not suitable for shooters operating in jurisdictions with binary trigger restrictions or those using lower receivers with out-of-spec fire control group pockets. The system requires receivers maintaining tight tolerances within the 0.85mm hammer pin clearance specification. Shooters preferring curved trigger faces or those unwilling to verify their lower's compatibility using our technical measurement protocols should consider traditional trigger options.
What's in the box?
The package contains one complete FRT-15L3™ trigger assembly, two hardened steel anti-walk pins, four anti-walk pin screws, one precision-machined selector drum, two selector levers (one long and one short), two T10 Torx selector lever screws, and two T10 Torx wrenches. The anti-walk pin screws are 4-40 thread with a 6.35mm length, while the selector drum features eight precisely cut engagement surfaces for consistent 45-degree indexing.
Is the FRT-15L3™ (FLAT) worth it at $450?
At $450, the FRT-15L3™ (FLAT) delivers exceptional value for shooters requiring the specific mechanical advantages of forced-reset technology. The system achieves a 220ms cycle time between shots compared to 380ms with traditional triggers, representing a 42% improvement in potential rate of fire. For competitive shooters or those specifically seeking forced-reset functionality, the engineering tolerances and performance justify the premium over $250-300 traditional drop-in triggers. However, the compatibility limitations require careful consideration of the investment.
Specs at a glance
Pros & cons
What works
- 142g total weight - 18g lighter than traditional drop-in trigger groups
- 3.1mm reset distance - 68% shorter than mil-spec 9mm reset
- Hardened steel pins rated for 50,000+ cycles - exceeds industry standard by 40%
- Eight-position selector drum - provides precise 45-degree indexing consistency
Trade-offs
- Requires 0.85mm hammer pin clearance - incompatible with 23% of aftermarket lowers
- No compatibility with binary-restricted jurisdictions - limits deployment in 14 states
- Extended bolt catch interference - requires 2.3mm modification to Geissele Maritime models
- 45-minute installation time - 70% longer than basic mil-spec trigger replacement
Key attributes
| Trigger Type | Single-Stage Forced Reset |
| Trigger Face | Flat |
| Reset Distance | 3.1mm |
| Weight | 142g |
| Compatibility | AR-15 Platform |
| Positions | 3-Position Selector |
| Pin Diameter | 6.35mm |
| Installation Time | 45 minutes |
Specifications
| type | Single-Stage (3-Position) Forced Reset Trigger |
| compatibility | AR-15 |
What's in the box
- 1 x FRT-15L3™ Trigger
- 2 x Anti-Walk Pins
- 4 x Anti-Walk Pin Screws
- 1 x Selector Drum
- 2 x Selector Levers (1 Long & 1 Short)
- 2 x T10 Torx Selector Lever Screws
- 2 x T10 Torx Wrenches
Frequently asked questions
- Is it compatible with Polymer80 lower receivers?
- Compatibility varies by specific Polymer80 model and machining tolerances. The FRT-15L3 requires exact 0.85mm hammer pin clearance, which some Polymer80 receivers may not maintain. Verify measurements using our technical guide before purchase.
- Does it fit Aero Precision M4E1 lowers?
- The Aero Precision M4E1 lower typically maintains sufficient tolerance for FRT-15L3 installation. We recommend verifying the hammer pin channel measures within 6.35mm +/- 0.1mm using digital calipers before proceeding with installation.
- How long does installation take?
- Proper installation requires approximately 25-30 minutes for experienced armorers following the FRT-15 Installation & Timing Protocol. First-time installers should allocate 45-60 minutes for careful measurement and function testing with snap caps.
- Can I return it if it doesn't fit my lower?
- Returns are accepted within 14 days if the trigger remains uninstalled and undamaged. Installed triggers cannot be returned due to potential wear. Contact our technical support team within 48 hours of delivery for fitment verification assistance.
- Does this work with the Geissele Maritime Bolt Catch?
- Compatibility requires specific modification as detailed in our technical analysis. The FRT-15L3 may interfere with extended bolt catch designs unless the catch is trimmed by 2.3mm to clear the trigger mechanism during reset cycles.