The Heretic Custom Assembly Process

Material & Component Selection

Material and component selection at Heretic Custom Arms is the result of years of trial, testing, and failure analysis. Every part is chosen to balance performance, durability, and system reliability based on the rifle’s intended application.

Barrel Selection

Barrels length and materials are selected to match the rifle’s role, balancing function, quality, and longevity.

• CrMoV Steel (QPQ Nitrocarburized):
  Selected for duty and hard-use rifles, offering superior corrosion resistance, wear resistance, and extended barrel life.
• 416R Stainless Steel:
  Used for precision and match-grade applications where consistency, machinability, and accuracy are prioritized.

Upper & Lower Receivers

Receivers are manufactured from 7075-T6 aluminum and come standard with Type III hard-coat anodizing for maximum strength and wear resistance.

• Forged receivers are used for traditional duty and sporting builds.
• Billet receivers are selected where design enhancements or specialized configurations are required, including enlarged trigger guards to accommodate gloved use.

Bolt Carrier Group (BCG)

Bolt carrier groups are selected for durability, smooth cycling, and long-term reliability.

• Nickel Boron–coated bolts manufactured from Carpenter 158 or 9310 steel
• All bolts undergo Magnetic Particle Inspection (MPI) to detect microscopic cracks or structural defects before assembly

This ensures structural integrity under repeated cyclic stress.

Gas System

• Steel gas blocks are standard due to superior heat tolerance and durability compared to aluminum alternatives
• Superlative Arms adjustable gas blocks are available for advanced tuning, reduced recoil impulse, and improved reliability
• Gas system selection is matched to barrel length and intended use

Handguards / Rails

Handguards are constructed from 6061-T6 aluminum for strength and weight efficiency.

• M-LOK interfaces or drilled-and-tapped designs are selected based on accessory and mounting requirements

Fire Control Components

Trigger systems are selected based on the rifle’s purpose and customer preference.

• Mil-spec single-stage triggers
• Nickel-Teflon-coated single-stage triggers
• Match-grade two-stage nickel-boron-coated triggers
• Available in flat or curved configurations

Controls & Small Components

• Safety selectors:
  • Mil-spec 90° throw
  • 60°/90° ambidextrous safety options
• Chrome silicon springs for increased fatigue life

Muzzle Devices

Muzzle devices are selected based on suppression use and recoil management.

• Standard A2 brake
• Single-port Plan B hub adapter brake for suppressed configurations
• Three-port muzzle brake for unsuppressed applications

Charging Handle

• Extended non-ambidextrous charging handle (standard)
• Ambidextrous charging handle available for enhanced manipulation

Buffer System

Buffer systems are tuned to complement the gas system and overall rifle timing.

• Standard carbine buffer system
• Geissele Super 42 braided buffer spring
• KAK K-Spec enhanced H1 buffer system

Furniture & Ergonomics

• Stocks:
  • Magpul MOE SL
  • B5 Systems Bravo
  • Leapers UTG Pro
• Grips:
  • A2
  • Spike’s Tactical Pro Grip
  • Magpul MOE or MOE-K2

Magazines & Accessories

• Magazines: Magpul or Lancer (capacity compliant with state regulations)
• Accessories: M-LOK QD mounts or QD end plates
• Optics & scopes: available upon request

All components are individually inspected prior to assembly. Parts are checked for dimensional accuracy, proper tolerances, material quality, and manufacturer specifications. Any component that does not meet Heretic standards is rejected before entering the build.

Receivers and components are finished according to customer specifications in either custom Cerakote colors/patterns or Type III hard-coated anodized black. All coatings are applied with attention to coverage, adhesion, and durability to ensure long-term protection under hard use.

Upper receivers are assembled with strict attention to fit, alignment, and mechanical function.

• Barrels are thermally fitted to ensure a tight, consistent interface with the upper receiver.
• Headspace and barrel timing are verified prior to final torque.
• Gas blocks and tubes are aligned to ensure proper gas flow, secured, and mechanically staked.
• Handguards and muzzle devices are installed and torqued to specification.
• Bolt carrier groups are inspected for proper gas ring tension, extractor function, and carrier key torque and staking.
• Charging handle engagement and extractor spring tension are verified.
• All friction surfaces are properly lubricated prior to testing.

Lower receivers are assembled to ensure consistent trigger operation and control function.

• Fire control groups are installed and checked for proper sear engagement, release, and reset.
• Controls, safety selector, and grip are installed using appropriate torque and thread locking compounds.
• Buffer tube, castle nut, end plate, and stock are installed and inspected for proper alignment and retention.
• All mating surfaces and moving components are lubricated as required.

Each rifle undergoes a comprehensive function check prior to live fire, including trigger operation, safety engagement, bolt catch function, magazine release, charging handle operation, and buffer system tension. The rifle is inspected for obstructions and proper cycling.

Rifles are range-tested to confirm reliability and performance.

• Barrel break-in is performed.
• Gas system timing, ejection pattern, recoil impulse, and muzzle rise are evaluated.
• The rifle is inspected for gas leakage during sustained fire.
• Accuracy is verified at normal operating temperature, with groups tested at 50 yards.
• Final cleaning is completed, followed by lubrication with Heretic's proprietary oil.

All rifles are shipped in a protective soft case to the FFL of your choice and include a signed Quality Control target card documenting test conditions and performance data. Each card records ambient temperature and weather conditions, average velocity across a five-shot group with the ammunition used, standard deviation, extreme spread, and complete ballistic information for the test load.