KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2
KA Tech MAC Polarstars F2 AR8 HPA M4 Stuby Type 5 Skeletonized Cerakote Splatter - KA Tech Airsoft - Polarstar F2

KA Tech MAC Polarstar Stuby AR8-5 HPA M4

$1,350.00
Upper Receiver
Polarstar HPA Engine

Which Polarstar HPA Engine Should You Choose?

All FPS figures are measured with our standard 180mm 6.02 inner barrel and KA Tech's tuned hop-up, bucking, and regulator combination.

Kythera

250–400 FPS · 350 FPS @ ~100 PSI · Semi-auto only

Purely mechanical — no electronics, no full-auto. Just air, BBs, and go, with a realistic trigger pull, break, and reset. Great for training, Milsim, or fields that are hesitant about HPA rifles.

Jack

250–410 FPS · 350 FPS @ ~100 PSI · Up to 50 RPS full-auto

Our entry-level HPA engine. Fast semi-auto with real full-auto capability.

F2

250–440 FPS · 350 FPS @ ~100 PSI · Up to 85 RPS full-auto

The best overall HPA engine on the market — the strongest combination of air efficiency, accuracy, range, consistency, and tune-ability.

Fusion Engine

250–500 FPS · 350 FPS @ ~55 PSI · Up to 75 RPS full-auto

The powerhouse. A clicky tactical trigger board delivers crisp trigger response for players who want the most power out of their rifle.

Our recommendation: First time going HPA? Go with the Fusion Engine. If you're committing real money to get into HPA, go all the way the first time so you're not stuck upgrading piece by piece down the road.
Barrel Length & Type

Standard Barrel vs. Speed Cannon

The standard outer barrel is a carbon fiber outer barrel with -14mm threads — the same setup you'll find on every airsoft rifle.

The Speed Cannon is a carbon fiber tube with integrated space for a tracer unit. You sacrifice 2in / 50mm of inner barrel length, but you get a recessed tracer unit and an aluminum cap that protects your carbon fiber. Speed Cannon fits Acetech Brighter C and R tracer units only.

Speed Cannon barrel detail Standard vs Speed Cannon barrel comparison Speed Cannon tracer unit recess

Up to 45 business days

Production starts the moment you order. Cancel any time before it begins for a full refund — no fee.

Made to order, ships in up to 45 business days

Trade in your rifle any time

Shipping & returns

Backed by KA Tech Warranty
HPA Specialists Since 2022
Trade in anytime — up to 70% back in store credit
3-month labor warranty — you only pay for parts

Every KA Tech rifle is built on internals and tuning we’ve spent the last four years perfecting. Our performance packages are the industry standard everyone else is chasing — if you want something that’s going to outperform everything else on the field, this is it.

The KA Tech MAC AR8 is built for players who want a super lightweight speedsoft rifle without giving up the feel of a full-size platform. This build pairs a full CNC aluminum and carbon fiber body with a compact, fixed Stuby stock, engineered to move fast and hit hard.

This rifle is built with top-tier internals and premium external components to give players a true performance advantage — made to perform at a high level while keeping the clean, signature look KA Tech is known for.

Choose the standard outer barrel configuration for a more traditional setup, or select the Speed Cannon configuration, which houses the tracer unit inside the carbon fiber barrel for a cleaner, more streamlined look. Both options are built to deliver fast response, excellent air efficiency, and strong consistency on the field.

Colors, CNC design, and specific requests can always be customized — just reach out.

Buying a KA Tech rifle isn’t where our relationship ends — it’s where it starts. Think of us as the best HPA technicians in the country, in your pocket, 24/7. Want to change your FCU tune? Swap parts? God forbid something goes wrong? We want to be the first call you make for anything HPA-related. When you buy a KA Tech rifle, you’re not just getting the best build on the field — you’ve got a full tech team behind every move you make.

  • Full CNC aluminum and carbon fiber construction
  • Cerakoted for an extremely durable, field-ready finish
  • Compact, fixed Stuby stock for a lightweight, low-profile platform
  • Built for extreme range, accuracy, and consistency
  • Premium HPA rifle platform with extensive customization potential
  • Choice of standard outer barrel or Speed Cannon configuration
  • Compatible with M4-style magazines
  • Tuned and tested with PTS EPM1 magazines and precision .25g BBs

Internal Parts

  • HPA Engine: PolarStar Kythera, Jack, F2 or Fusion Engine
  • Gearbox: MAC Airsoft HPA Gear Box V2 — Purple
  • Hop-Up Chamber: Maxx Model CNC Aluminum Hop-Up Chamber — M4E Pro or M4G GBB
  • Bucking: Maple Leaf Autobot Hop-Up Bucking or Maple Leaf SUPER Macron Hop-Up Bucking
  • Inner Barrel: Maple Leaf 6.02mm Airsoft AEG Tightbore Inner Barrel or Maple Leaf Crazy Jet Inner Barrel 6.02 or Prometheus 6.03 EG Tight Bore Inner Barrel
  • Internal Airline: Amped IGL Internal Airline – Standard — JACK™ / F2™ / Lavender

Performance

  • Fusion Engine reference spec: 350 FPS @ ~55 PSI, 250-500+ FPS adjustable range, up to 75 RPS full-auto
  • F2 reference spec: 350 FPS @ ~100 PSI, 250-440 FPS adjustable range, up to 85 RPS full-auto
  • Jack reference spec: 350 FPS @ ~100 PSI, 250-410 FPS adjustable range, up to 50 RPS full-auto
  • Kythera reference spec: 350 FPS @ ~100 PSI, 250-400 FPS adjustable range, semi-auto mechanical only (no full-auto)
  • Firing Modes: Semi / Full-Auto (mechanical Kythera is semi-only)

External Parts

  • Receiver: MAC AR8 Receivers — Type 5
  • Outer Barrel: Carbon Fiber Outer Barrel or MAC Carbon Fiber Speed Cannon
  • Handguard: MAC Carbon Fiber Handguard V, matched to your colourway
  • Stock: CQB Stubby Fixed Stock — Lancer Tactical
  • Trigger: Speed Airsoft HPA M4 Tunable Trigger — Blade / Purple
  • Production: Built to order — begins immediately upon purchase
  • Estimated Ship Time: Up to 45 business days (often less)
  • Need It Faster: Contact us to check current in-stock availability
  • Delayed Orders: If we can't meet this window, you may cancel for a full refund — no fee
  • Polarstar Manufacturer Warranty: 1 year on Polarstar components (engine, regulator, etc.)
  • KA Tech Labor Warranty: 3 months, 100% labor covered — you only pay for parts
  • Warranty Activation: Requires watching our 2-minute HPA do's & don'ts video
  • Cancellations: Accepted any time before shipping; 30% restocking fee applies once production has begun
  • Trade-Ins: 70% store credit / 50% cash refund if like-new, 60% store credit / 40% cash refund if used

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