BCA Level 2 Upgraded VFC Avalon MP5A4

Custom Gun Builds

Z Custom Airsoft Work

Trigger Board
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Level 2 High-Speed Build

  • PDI 6.05mm SUS304 Stainless Steel Inner Barrel OR Lambda 6.05mm SUS304 Stainless Steel Inner Barrel (depending on availability)
  • R Hop Installation for PDI Barrel
  • Lonex Hop Up Rubber
  • BTC Spectre MK.II Non-Bluetooth OR Jefftron Leviathan Computerized Trigger Board Bluetooth
  • Prometheus POM Piston Head with X-Ring
  • SHS 14T 7 Hole Lightened Piston
  • SHS Stainless Steel Cylinder
  • SHS CNC Aluminum Cylinder Head with Sorbo Pad
  • Guarder Tappet Plate with Enhanced Tappet Spring
  • SHS 13:1 High-Speed Gear Set
  • SHS High Torque Motor
  • 8mm Steel Bushings

This upgrade also covers all of the same points as the basic upgrade package but is also designed significantly enhance performance. The BTC Spectre Mk.II/Jefftron Leviathan is a highlight of this upgrade. They are fully computerized trigger boards that shortens your trigger pull and has a sector gear cutoff sensor so that your trigger will never jam, and your gearbox will always complete its cycle. While the BTC is of slightly better quality, the Leviathan makes up for it by having a Bluetooth function. Other features include battery voltage monitoring, adjustable levels of motor braking, programmable burst modes, the list goes on!

A high torque motor will be paired with a high-speed gear set to improve the rate of fire, trigger response, and overall efficiency. This replaces all drivetrain and air seal components within the mechbox with aftermarket parts that will be modified appropriately and installed to operate smoothly. Note that the drivetrain will be short stroked and a heavier spring will be necessary to maintain the same FPS output for the high-speed setup.

Trigger response will be improved significantly, and this upgrade service will give you a noticeable performance boost in the rate of fire as well. You should notice an improvement in accuracy, FPS consistency, the gearbox will also be much quieter and smoother.

Estimated ROF:

30 - 35 RPS with 11.1v lipo battery

Muzzle Velocity:

300 - 400 FPS, please indicate requested FPS range while ordering, for example, 370 - 400 FPS.


  • Estimated lead time: 2 - 4 weeks
  • Product may come with orange tip
  • We recommend using .28g ammo or heavier with our barrel group setups.
  • AEG Tuning Services Provided by Z Custom Airsoft Works

Why do we not build DSGs?

Here at BlackBlitz Airsoft, our tech team is extremely performance oriented so some may find it surprising that we do not build DSG (Dual Sector Gear). Through experience, we have found that DSG setups are largely impractical for field use. They are volume limited, and extremely inefficient compared to SSG (Single Sector Gear) setups. They also do not provide a better trigger response or rate of fire than a well-built SSG. DSG setups became an experimental fad from when people had not figured out how to build SSG setups properly. Our techs have built SSGs up to 60 RPS at 380 FPS on 11.1V. There is some merit for DSG setups once you begin to use 14.8V and are reaching 70+ RPS, but those are mere showpieces and not practical for field use. 

Why R Hop?

In order for one to understand RHop, one must understand the accuracy and range. With the amount of misinformation spread online, we have to clear a few things up first and define some terms.

Range: The distance your BB travels while maintaining a relatively flat trajectory.
Accuracy: The level of dispersion within your groupings at a certain range.
People often claim that different hop up setups gives more range - this is mostly untrue. Two BBs that leave a barrel at the same velocity with the same spin from the hop up will have the same trajectory and the same range. It does not matter how the hop is applied, or what type of material applied the hop. If muzzle energy is the same and the same BB weight is used, one hop up will not give more range than another unless one of them is incapable of applying enough backspin to the BB.

So, the point of upgrading a hop up is usually not to improve “range”, but more to improve accuracy at range applying hop in a more consistent manner in both spin rate and direction.

R Hop itself is a patch of silicone tubing that fits into the hop up window cut into the barrel. A good patch must be flush with the bore of the barrel and fit perfectly in the window. This patch provides an elongated contact area to provide a gentler, more consistent spin to the BB, as well as the ability to lift heavier BBs. Since it applies the spin directly on top instead of using a mound it decreases the amount of shift in the hop applicator as well as the resistance to the BB, therefore increasing consistency between shots, and decreasing FPS loss from applying more hop.

Our normal turnaround time is roughly two weeks, however, we often complete the work much faster. We also sometimes experience unexpected delays due to tech backlog, unanticipated compatibility issues, etc. so our stated turnaround times are only estimates. We will not guarantee a gun returned by a certain date, but we will do our best to meet your deadlines. If a work order is not completed by the expected date, we will not offer a refund or discount on the work order unless the delay is deemed excessive at our discretion.

At BlackBlitz Airsoft we care about the quality of our tech work. Upgrades and repair services performed through BlackBlitz Airsoft are guaranteed for parts and workmanship for a period of 90 days unless stated otherwise. If a problem occurs or there is a concern with the work we have done, please contact us for troubleshooting. If it is determined that a part was defective or work was done improperly, we will provide shipping instructions and cover return shipping.

Only problems occurring during normal use are covered. User error and misuses such as using low-quality ammunition or excessive power supplies are not covered.

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