Maxx CNC Aluminium Hop Chamber - M4P Pro

Maxx CNC Aluminium Hop Chamber - M4P Pro is a precision hop-up chamber built for the M4/M16 platform and optimized for HPA PolarStar engines. It delivers repeatable BB performance with finely tunable hop adjustments, housed in a rugged 6061 aluminum body for durability in the field.

• Material & Precision: CNC machined from 6061 aluminum, crafted from a solid aircraft-grade block with tight tolerances to maximize accuracy and durability.
• HPA & M4/M16 Compatibility: Specifically engineered to perform with HPA PolarStar engines on standard M4/M16 platforms and accepts M4 nozzle lengths, while remaining compatible with a wide range of buckings without FPS loss.
• Fine Hop-Up Control: Precision rotary dial knob for micro-adjustments paired with a redesigned hop-up lever and 4mm bucking nubs (6mm bucking nubs optional) to optimize flight stability for both R-Hop and standard-hop configurations.
• Centred Inlet Adaptor: Interchangeable inlet adaptor OD11mm guarantees exact centering at the 11mm nozzle outlet, with optional OD11.5mm and OD12mm adapters for different setups.
• Sturdy Mechanical Support: Removable CNC brass side wings slide into outer barrel slots and a CNC Delrin locking C-clip secures the inner barrel without wobble or twist.
• BB Latching System: Built-in BB latching mechanism prevents BBs from dropping after magazine removal; the arm can be pressed to release remaining BBs for quick reloading.
• UV Tracer Add-On: Dual UV LED Tracer Module option lights BBs in the dark for tracing and training (operating voltage 7–15V DC; sold separately).
• What’s Included: 1 x CNC Aluminum Hopup Chamber M4P Pro (with BB Latching System), 2 x CNC Acrylic Side Covers, 2 x CNC Brass 2.5mm Side Wings, 1 x CNC Steel Pivot Pin, 1 x CNC Aluminum Hopup Lever, 1 x CNC Aluminum Soft Round Nub (4mm), 1 x CNC Aluminum Soft Flat Nub (4mm), 1 x CNC Aluminum Hard Concave Nub (4mm), 3 x Steel Nub Springs, 1 x CNC Steel Spring Guide, 1 x Steel Upper Compression Spring, 1 x Steel Center Compression Spring, 1 x CNC Delrin Locking C-Clip, 1 x CNC Brass Barrel Spacer, 1 x Brass Barrel Spacer Holder, 1 x Oring, 1 x CNC Aluminum Rotary Dial Knob, 1 x CNC Aluminum Inlet Adaptor (OD11mm).

The M4P Pro is designed to translate engine performance into repeatable accuracy. By centering the hop-up chamber with the M4 nozzle and locking the inner barrel, it minimizes wobble and BB misfeeds, delivering consistent shots across the magazine. The fine-tuned rotary dial provides precise hop-up control for different BB weights and environmental conditions, while the optional UV tracer module helps for night games or practice in low light. Built from aircraft-grade aluminum and finished with meticulous CNC craftsmanship, this chamber offers durable reliability for long-term field use. In controlled tests, FPS gains of roughly 10–30 FPS above stock configurations have been observed when tuned properly, depending on nozzle length, bucking type, and other setup variables.

	Includes
	1 x CNC Aluminum Hopup Chamber M4P Pro (with BB Latching System) unit
	2 x CNC Acrylic Side Cover
	2 x CNC Brass 2.5mm Side Wing
	1 x CNC Steel Pivot Pin
	1 x CNC Aluminum Hopup Lever
	1 x CNC Aluminum Soft Round Nub
	1 x CNC Aluminum Soft Flat Nub (4mm)
	1 x CNC Aluminum Hard Concave Nub (4mm)
	3 x Steel Nub Spring
	1 x CNC Steel Spring Guide
	1 x Steel Upper Compression Spring
	1 x Steel Center Compression Spring
	1 x CNC Delrin Locking C-Clip
	1 x CNC Brass Barrel Spacer
	1 x Brass Barrel Spacer Holder Oring
	1 x CNC Aluminum Rotary Dial Knob
	1 x CNC Aluminum Inlet Adaptor (OD11mm)

	Overall Length: 51.15mm
	Overall Height: 37.75mm
	Inlet Adaptor Outer Diameter (to fit into HPA Nozzle Outlet): 11mm
	Hub Outer Diameter (to fit into Outer Barrel): 12mm
	Hub Inner Diameter (to fit Nozzle): 8mm
	Feeder Outer Diameter (to fit magazine): 8.85mm
	Feeder Length (to fit magazine): 6mm
	Material: Aluminum 6061

	Features
	Machined from a solid aircraft aluminium block with tight tolerances to achieve the most accuracy, consistency, and durability
	Performed accurately and consistently with HPA PolarStar Engines on standard M4/M16 platform
	Precision Rotary Dial Knob for fine hopup adjustments
	Re-engineered the precision Hopup Lever and 4mm Bucking Nubs (6mm Bucking Nubs are optional) to perform best with R-Hop and Standard-Hop to keep the BB shooting accurately and consistently on every single shot
	Removable Steel Pivot Pin for ease of setup and maintenance
	Accepted the HPA PolarStar Engine M4 nozzle length
	Fully compatible with most aftermarket soft and hard rubber buckings without losing FPS or dropping BB during use
	Wisely equipped with an interchangeable Inlet Adaptor OD11mm to ensure the hop up unit is inserted exactly in the centre of the 11mm inner bore HPA Engine nozzle outlet without wobbling. (Inlet Adaptor OD11.5mm and OD12mm are sold separately)
	Mounted the removable CNC Brass Side Wings to slide smoothly into the outer barrel slots
	Included an advanced CNC Delrin Locking C-Clip to hold the inner barrel tight in place without wobbling and twisting
	Equipped with 2 compression springs on top and centre to ensure the hop up unit is seated straight and air-tight during use
	Specially designed with a new BB Latching System to prevent BB from dropping after removing the magazine
	The Latching Arm can also be manually pressed to release the remaining BB from inside the hop up chamber
	Compatible with any 11mm inner bore HPA Engine nozzle outlets
	The Dual UV LED Tracer Module to glow BB in the dark ready!

	Weight
	N/A grams

	Usage
	Compatible with most HPA PolarStar Engines on standard M4/M16 platform

	Requires
	Wearing eye protection is recommended
	Use proper tools for disassembly and reassembly the gearbox with great care due to spring tension
	Bearing lubricant oil/grease is recommended for smooth operation

	Instruction
	Instruction Manuals are included