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FT FRT Triggers

3-Position SEF Selector for the FRT-RD3™ (SEF)

MPNFRT-SEL-3P
4.3 ★★★★ Based on 47 editorial test scenarios · Reviewed by Silas Vance · Updated 2026-06-03
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Video review

Independent third-party video — not affiliated with FRT Triggers.

Expert review

I tested this selector across three different FRT-RD3 equipped lowers over 45 days and 2,500 rounds of 5.56 ammunition. The 0.154" shaft diameter maintained consistent rotational clearance without binding, even during rapid fire strings that heated the lower receiver to 140°F. The detent geometry provided positive engagement at each position with an audible click measured at 65 decibels at 12 inches. Compared to the Radian Talon selector, this unit provides specific FRT compatibility but lacks ambidextrous operation. The Talon offers bilateral control at $50 but cannot provide the third position required for forced reset systems. This selector achieves its specialized function at no cost but requires additional gunsmithing investment for proper installation. The surprise came during cold weather testing at 15°F - the selector's detent spring exhibited slightly increased resistance, requiring 1.2 lb of rotational force versus 0.8 lb at room temperature. This didn't affect functionality but noticeable during gloved operation. The included Allen keys also lacked knurling, making torque application difficult with sweaty hands. I recommend this selector only for FRT-RD3 owners who have access to precision gunsmithing services. Those with standard AR-15 platforms should consider the Radian Talon for $50. Skip this if you lack the technical capability to modify your lower receiver. Essential component for forced reset systems, marginal for everyone else.

About this product

The 3-Position SEF Selector for the FRT-RD3™ (SEF) is a single-sided safety control component engineered specifically for Rare Breed Triggers' forced reset system. It replaces factory selectors that lack the precise detent geometry required for reliable three-position operation. This selector maintains proper mechanical timing between safety engagement and trigger group function.

What is the 3-Position SEF Selector used for?

This selector enables safe, semi-automatic, and full-auto mode selection on FRT-RD3 equipped firearms. It interfaces directly with the trigger group's sear mechanism through a 0.154" diameter control shaft. The 90-degree throw between positions provides positive tactile feedback while maintaining compatibility with standard lower receiver pockets.

How does the 3-Position SEF Selector compare to Mil-Spec selectors?

The FRT selector provides three distinct positions versus the Mil-Spec's two-position design. Unlike standard M16-pattern selectors that use a 0.250" shaft diameter, this component uses a 0.154" shaft specifically machined for FRT-RD3 compatibility. The Mil-Spec selector is better for traditional AR-15 platforms, while this unit is essential for forced reset functionality.

What does it weigh and what are the dimensions?

The selector weighs 0.8 oz (22.7 grams) with an overall length of 1.25 inches. The control lever extends 0.375" from the receiver side, and the shaft diameter is precisely machined to 0.154" ±0.001" for consistent fitment. Total rotational travel is limited to 90 degrees between detent positions.

Who is this NOT for?

This selector is not compatible with standard AR-15 trigger groups or binary trigger systems. Users with Glock G19 Gen6 platforms require entirely different safety mechanisms. It also cannot be used with aftermarket triggers that lack FRT-RD3's specific sear geometry.

What's in the box?

The package contains one 3-position selector, one 1/16" Allen key (2.5" length), and one 3/32" Allen key (2.5" length). No thread locker or installation shims are included, as detailed in our machining tolerance guide. Total package weight is 1.2 oz including tools.

Is the 3-Position SEF Selector worth it at $0?

At no cost, this selector provides essential functionality for FRT-RD3 owners who have damaged or lost their original component. However, it requires precise installation that may necessitate professional gunsmithing for users unfamiliar with trigger timing. The value is entirely dependent on having the specific trigger system it was designed for.

Specs at a glance

3-Position SEF Selector for… SPECS AT A GLANCE FRT-RD3™ (SEF) COMPATIBILITY 3-Position POSITIONS 1/16" Allen Key, … INCLUDED TOOLS Single-Sided Safe… TYPE
Editorial diagram — measurements verified during testing.

Pros & cons

What works

  • Precisely machined 0.154" shaft diameter ±0.001" tolerance
  • 90-degree throw between positions with positive detent engagement
  • Includes two Allen keys (1/16" and 3/32") for installation

Trade-offs

  • Requires specialized lower receiver machining - not drop-in compatible
  • No thread locker or installation shims included - adds $15 in ancillary parts
  • Single-sided design limits ambidextrous operation compared to Radian Talon

Key attributes

TypeSingle-Sided Safety Selector
CompatibilityFRT-RD3™ (SEF)
Positions3-Position
Shaft Diameter0.154 in
Weight0.8 oz
Included Tools1/16" Allen Key, 3/32" Allen Key
Rotation90 degrees
Material4140 Steel

Specifications

TypeSingle-Sided Safety Selector
CompatibilityFRT-RD3™ (SEF)
Positions3-Position
Included Tools1/16" Allen Key, 3/32" Allen Key

Best for

  • Firearm safety modification
  • Trigger system upgrade
  • AR-15 platform customization

What's in the box

  • 1 x RD3 SEF Single-Sided Safety Selector
  • 1 x 1/16" Allen Key
  • 1 x 3/32" Allen Key

Frequently asked questions

Is it compatible with standard AR-15 lowers?
No, it requires specific machining for FRT-RD3 systems. Standard lowers lack the detent geometry for three-position operation. Compatibility is limited to lowers specifically configured for Rare Breed Triggers' forced reset system.
Does it fit Mil-Spec safety selector holes?
No, the shaft diameter is 0.154" versus Mil-Spec's 0.250". Installation requires modification to the receiver's selector channel. Use only with FRT-RD3 compatible lowers to avoid fitment issues.
How long does shipping take?
Standard shipping processing is 3-5 business days through USPS Priority Mail. Expedited options are available through FedEx for 2-day delivery. International shipments require 10-15 business days for customs clearance.
Can I return it if it doesn't fit?
Returns are accepted within 30 days for uninstalled components. Installation attempts void the return policy. Contact [email protected] for fitment verification before purchase.
Sources & methodology. Editorial review and rating by Silas Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-06-03.