VFC MP7 HPA Drop-In Gearbox — Customer-Supplied PolarStar Edition
Bring the engine. We do the hard part.
Due to overwhelming demand and the scarcity of VFC MP7 AEGs, Bull Craft now offers a Customer-Supplied Engine (BYO) Drop-In HPA Gearbox. You send us your PolarStar F2 or Jack, and we build a fully assembled, tuned, and ready-to-run MP7 HPA gearbox around it.
This is the same proven Bull Craft drop-in system—minus the engine—professionally integrated, aligned, and tested in-house. No guesswork. No DIY frustration. Just a locked-in HPA solution that works.
?️ What’s Included
• Custom MP7 gearbox designed, printed, processed, and assembled in-house
• Precision engine integration — engine locked solid, zero alignment issues
• Choice of flat/straight or curved trigger
• 6.03mm upgraded inner barrel
• CNC-machined anodized aluminum outer barrel
– 14mm CCW or 12mm CW (original spec)
• Upgraded bucking for proven consistency
• OEM hop-up unit (Bull Craft hop-up in development)
• Printed barrel safety cap for shipping
• Spec sheet tuned for low-altitude, humid environments
Shipped fully assembled and tuned — ready to drop in and play.
? What You Provide
• Your PolarStar F2 or Jack engine (shipped to Bull Craft for integration)
• If your engine does not include a macro line, an Amped IGL is required
• Optional upgrades available separately (Amped IGL, GSI Aluminum Hop-Up Arm)
⚠️ Important Notes
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You must ship your engine to us for this build
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You do NOT need to send your MP7 unless you want full install service ($75)
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If your engine requires servicing (cleaning, o-rings, rebuild parts), we will contact you before proceeding with any added cost
? Performance & Install Highlights
• Engine is positively locked — no shift, no misalignment
• Minimal body modification required
• Hop-up and bucking serviceable without voiding warranty
• Trigger install requires care — video guides provided
• Excellent air efficiency and reliability
• Trusted worldwide by MP7 HPA users
? Why This Exists
VFC MP7 AEGs are no longer produced and are only available second-hand. This option allows customers to reuse their PolarStar engine and still get a true Bull Craft drop-in solution—without hunting down a donor gun.
You bring the engine.
We deliver the solution.
