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Preparing your AR-15 lower

This video is a step by step guide on how to prepare your AR-15 lower for your 50-BMG upper receiver. 

 

πŸ› οΈ Big Kahuna Guns Support

Welcome to the Big Kahuna Guns Support Center. Whether you’ve just purchased your Raptor 50 or are looking for maintenance tips, troubleshooting help, or warranty info β€” you’re in the right place.

If you still need help after reviewing this page, feel free to contact us at [email protected] or call (813) 790-7220.

πŸ”° Getting Started

Read the Owner’s Manual

Before handling your Raptor 50, it’s essential to read the full product manual. It includes setup instructions, safety guidelines, and maintenance recommendations.

πŸ“„ Download the Raptor 50 Manual (PDF)

Initial Setup

  • Your Raptor 50 is a single-shot .50 BMG upper designed to install on a standard AR-15 lower receiver.
  • A heavy-duty hammer and spring kit is included and must be installed for safe function.
  • A fixed stock is required β€” collapsible stocks are not recommended due to the heavy recoil of the .50 BMG round.

πŸ’‘ Need help installing the hammer or attaching the upper?

Visit the FAQs or email us for assistance.

🧰 Maintenance & Cleaning

Field Stripping & Reassembly

  • Use a standard 3/8” wrench to remove the bolt handle.
  • Clean the firing pin, bolt head, and chamber after each session.
  • Always inspect for unusual wear or damage before firing.

Barrel Break-In Tips

  • Clean the barrel thoroughly before first use.
  • Follow a break-in procedure of 1 shot – clean – repeat for the first 10–20 rounds, then scale up to 2–3 shot groups.
  • Use copper solvent to remove fouling, and always push patches from breech to muzzle.

πŸ”§ Recommended Products

  • High-temp synthetic gun oil
  • Copper cleaner
  • Bore guide
  • Muzzle brake brush

⚠️ Common Issues & Troubleshooting

Hard Extraction After Firing?

  • Re-close and open the bolt quickly β€” this often clears the casing.
  • If stuck, do not use force. Instead, leave the bolt open and use a 3/8" rod through the barrel to safely remove the casing.

Failure to Fire?

  • Wait 2 full minutes (in case of a hangfire) before opening the bolt.
  • Inspect the round for primer strike β€” discard damaged ammo safely.

Firing Pin Not Moving Freely?

  • Disassemble and clean the bolt.
  • If the pin is damaged, do not fire the rifle. Contact us for a replacement.

🧼 Safe Ammo Use

Only use new, factory-loaded, commercial .50 BMG ammunition from reputable manufacturers.

❌ Do not use:

  • Military surplus ammo
  • Reloaded or handloaded rounds
  • Wet, corroded, or damaged cartridges

⚠️ Use of reloaded or surplus ammo voids warranty and may cause serious injury or damage.

πŸ”’ Storage & Safety Reminders

  • Store your Raptor 50 unloaded, with the bolt removed, in a secure location.
  • Keep out of reach of children and unauthorized users.
  • Always wear eye and ear protection when firing.
  • Never fire with bystanders to the side of the muzzle brake.

For detailed safety instructions, visit our Safety Information page.

πŸ“ Warranty Information

Your Raptor 50 comes with a 1-year warranty from the date of purchase against manufacturing defects. The warranty:

  • Covers: parts and labor for defects in materials or workmanship.
  • Does not cover: damage from modifications, poor maintenance, reloaded ammo, or misuse.

πŸ“¦ To submit a warranty claim, contact us at [email protected] and include:

  • Serial number
  • Date and place of purchase
  • Description of the issue
  • Photos if available

πŸ™‹ Still Need Help?

πŸ“§ Email: [email protected]

πŸ“ž Call: (813) 790-7220

Raptor 50 Owners Manual and Safety Information

Updated 5/2/2025

Download PDF Manual