Heritage Performance Recoil System

15LB Custom Tuned Setup for Radian RAMJET SIG P365XL / XMACRO 3.7" Builds

The purpose-selected captured recoil setup for the longer Radian RAMJET + AFTERBURNER configuration and other performance-oriented 3.7" SIG P365 builds.

The Heritage Performance Recoil System

If you saw the viral “flattest / no-recoil SIG P365 RAMJET build” video and came looking for the recoil system discussed in it, you found the Heritage product family. This listing is specifically for the longer 15LB, 3.7" P365XL / XMACRO version.

Running the original 3.1" P365 / P365X RAMJET instead? Choose our separately listed Heritage Performance Recoil System for the shorter 3.1" recoil-system length.

3.7" XL / XMACRO Fitment at a Glance

Important: This Is the 3.7" RAMJET Recoil System

This listing is specifically for the longer P365XL / P365-XMACRO 3.7"-length recoil system. P365XL and standard non-integrally-compensated P365-XMACRO upper assemblies use the longer 3.7" recoil-system format. It is the correct length for compatible builds using a 3.7" XL / XMACRO slide with the Radian RAMJET + AFTERBURNER made for that platform.

It is NOT the shorter P365 / P365X 3.1" RAMJET recoil assembly, which we offer in a separate Heritage listing, and it is NOT the P365-FUSE 4.3" recoil assembly.

Purpose-Selected for the Long RAMJET Build

The Heritage Performance Recoil System was selected for 3.7" P365XL / P365-XMACRO performance builds, especially the longer Radian RAMJET + AFTERBURNER configuration where gas is redirected to help control muzzle movement.

When the 3.7" Radian system is installed, the upper reaches approximately P365-FUSE overall length. The recoil assembly, however, still fits the internal geometry of the 3.7" XL / XMACRO slide—so this is the correct length category for that build.

3.7" RAMJET or 3.1" RAMJET?

Why the 15LB Setup?

This configuration uses a 15LB performance spring on a captured stainless steel guide rod. It is our preferred starting point for many 3.7" compensated, ported, optic-equipped, and performance-oriented P365 builds.

The goal is a balanced recoil impulse and smooth cycling while retaining enough spring force for the longer slide assembly. Because every build is different, final reliability must always be confirmed with the exact slide, optic, ammunition, and compensator being used.

What “Custom Tuned” Means

Heritage purpose-selects the 15LB spring weight and captured stainless guide-rod configuration for this performance application. It is a build-category tuning setup—not an individually fitted or guaranteed solution for every firearm, ammunition load, or aftermarket component combination.

Ideal For

• 3.7" SIG P365XL performance builds
• 3.7" SIG P365-XMACRO builds using a compatible non-integrally-compensated slide
• Radian RAMJET + AFTERBURNER systems made for 3.7" P365XL / XMACRO slides
• Custom compensated or ported 3.7" P365 slide assemblies
• Optic-equipped carry, range, and competition-style builds
• Shooters tuning slide cycling and recoil impulse

Premium Features

• Complete captured recoil spring and guide rod assembly
• 15LB custom tuned performance spring configuration
• Stainless steel guide rod construction
• 3.7" XL / XMACRO recoil-system length
• Purpose-selected by Heritage for longer compensated builds
• Premium upgrade for serious P365 builders

Compatibility

Designed for compatible 9mm P365XL / P365-XMACRO 3.7"-length slide assemblies.

• SIG P365XL 3.7" slide assemblies
• SIG P365-XMACRO 3.7" non-integrally-compensated slide assemblies
• Radian RAMJET + AFTERBURNER 3.7" P365XL / XMACRO builds
• Many compatible custom 3.7" P365 slide platforms

9mm only. Not compatible with P365XL .380, 3.1" P365 / P365X recoil-system applications, or the 4.3" P365-FUSE recoil-system application. The Radian 3.7" RAMJET + AFTERBURNER itself is not intended for the OEM integrally compensated XMACRO COMP slide.

Included

• One 3.7" Heritage Performance Recoil System
• 15LB captured recoil spring assembly
• Stainless steel guide rod
• Heritage premium retail packaging

Not Included

• Slide
• Barrel
• Radian RAMJET or AFTERBURNER
• Optic or iron sights
• Grip module / frame
• Firearm

Want the Complete RAMJET Upper Package?

The SIG Store Heritage also offers complete, professionally assembled Radian RAMJET slide packages for builders who want an all-in-one upper instead of sourcing each component separately.

• Radian RAMJET barrel + AFTERBURNER compensator
• Genuine OEM SIG SAUER slide
• Installed optic options
• Installed Heritage tuned captured recoil system
• Professionally assembled complete upper configuration
• Available in select 3.1" compact and 3.7" extended RAMJET packages

See our other Heritage listings for current complete-package configurations and optic choices. Availability varies. This recoil-system listing does not include a slide, RAMJET, AFTERBURNER, barrel, or optic.

Frequently Asked Questions

Heritage Performance Note

This is the recoil setup we prefer as a performance starting point for many longer compensated and ported 3.7" P365 builds, including compatible P365XL / XMACRO Radian RAMJET configurations.

Recoil tuning is build-specific. Performance can vary with ammunition, slide mass, optic weight, compensator design, porting, lubrication, maintenance, and break-in. Test the complete firearm with the ammunition you intend to use. Confirm safe operation, reliable feeding and ejection, and consistent slide lock before relying on any defensive or competition setup.

Radian, RAMJET, AFTERBURNER, SIG SAUER, P365, P365XL, P365-XMACRO, and P365-FUSE are trademarks of their respective owners. The SIG Store Heritage is an independent seller and is not affiliated with or endorsed by those manufacturers.

Premium Parts. Tuned Configurations. Serious P365 Builds.

Built around the same performance-minded approach used in our Heritage Radian RAMJET, compensated P365, and custom slide packages.