HK416 Build – Experimenting with alternative setups

Here are the hard numbers from the previous mechbox test using an M150 spring and the 10.44: DSG


304.1 FPS
38 RPS (derived from Audacity audio analysis from video clip)
23.9 Amps continuous

Some may argue that this ROF is abnormally low for a DSG but as the initial goal of the build was the fastest-possible trigger response, the much slower, but much higher-torque ASG U-18000 motor was chosen and this goal was achieved. The output of the test pack is also not ideal to power a DSG (2200mah 25-50C 11.1v lipo – yields 55/110 amps nominal continuous/peak), a possible contributing factor to the sub-40 RPS number.

The FPS however, is quite low and not quite competitive even for indoor play, so a swap was made to a Prometheus M170 spring to bring the FPS up.


The numbers:
341.1 FPS
22 RPS
36.8 Amps continuous

Metrics are improved but at the expense of amp draw. Peak/start-up amp draw exceeds what can be reliably provided by a standard buffer tube lipo (32.5/65 amps nominal continuous/peak). Extended testing using simulated skirmish shot patterns revealed that these batteries would not reliably power the gun for any period of time. There is definitely merit to this setup especially for another gun that is able to accommodate a large battery (eg: full stock ARs), however it simply is not feasible for this particular build with the battery space constraints in the buffer tube.

After some discussions with Z, an alternative setup was chosen and the DSG was discarded in favour of running an SSG.


Using M100 spring; 10.44:1 SSG
352.1 FPS
25 RPS
13.4 Amps continous

As the M170 setup is not viable for this particular platform, comparing the videos and metrics between the M150 DSG and M100 SSG metrics, some conclusions can be easily drawn.

  • While the cycle completion time for an SSG is longer than DSG, the difference is close to undetectable
  • Achieving competitive, extended-use FPS for a small battery setup on a DSG is not possible
  • For almost half the amp draw, while the ROF is lower, the FPS on the M100 SSG is much more useful
  • The ASG motor gives astoundingly low consumption values for a high-performance setup

I will be leaving the setup with the M100 SSG as-is and potentially move up to an M110 in the near future. I’ll update with another post with revised amp draw values.

Here are some pics of the gun, completed.



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