Classic Army / Knight's Stoner 96 HPA Gearbox
Choose One of 3 Configurations
Gearbox Only
Gearbox + Nozzle
Gearbox + Nozzle + M249 Fitment Kit
(REQUIRED if using a standard / NON-M249 PolarStar F2 or Jack)
⚠️ IMPORTANT COMPATIBILITY NOTICE — READ BEFORE PURCHASE
This gearbox is NOT compatible with the PolarStar V2 Trigger Board due to interference between the body pin and board placement.
➡️ We have removed V2 trigger board support entirely to prevent install issues and customer frustration.
? Critical Note for F2 & Jack Users
If you are running a standard (NON-M249) PolarStar F2 or Jack, you MUST select the option that includes the M249 Fitment Kit.
The M249 Fitment Kit includes:
Plug Board
Bullet Valve Lead
Trigger Switch (included as a backup if your build is missing one)
❌ No kit = improper fitment
❌ No kit = alignment issues
❌ No kit = unreliable operation
If your engine is M249-specific, you do NOT need the kit — those parts ship with the engine from PolarStar.
? Product Overview
Upgrade your Knight’s or Classic Army Stoner 96 with a purpose-built Bull Craft HPA Gearbox, engineered as a true drop-in solution for PolarStar engines. Designed to eliminate guesswork, shims, and alignment headaches, this gearbox locks everything where it belongs.
✅ Core Features
Dual nozzle alignment points for precise tuning
Updated specifications based on tech testing and customer feedback
Built-in compatibility with PolarStar F2 & Jack
No shim kit required for engine installation
? Nozzle Requirement — READ THIS
PolarStar F2 & Jack require the #3 M249 nozzle
Select the Gearbox + Nozzle option if you don’t already have one
?️ Hop-Up Modification Required
To ensure proper BB feeding:
The hop-up window must be elongated/opened
This has been required on both Bullgear and OEM hop-ups
This is a known and expected step for proper function.
? NEW DESIGN FEATURES
Front-side wire & FCU pass-through for clean routing
Rear FCU cavity for organized rear wiring
Precision-aligned front pin — no shims needed for Jack or F2 installs
Built for our gearbox.
Built for PolarStar.
Built to work the first time.
