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AWS Scorpion HRC-X500 Review

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AWSAirsoft is an online business that makes computer FETs run by PsyphyerVII. His FETs are usually very hard to get but I've been lucky to get a few of his Scorpions.


For the past few months I've installed and used the Scorpion model version HRC-X445 in my SCAR-L, and in my ACR. The features of the Scorpion can be found here. And there's a little bit more information about the latest x500 on the front home page.


Please note that although I've got the Scorpion model, I'm only using it up to the Pulse emulation. I have not installed the hop chamber sensor, nor the bolt catch or charging handle sensors.


As such I won't be going through the entire product review but only for what I've tried on the x500.


Here's pic comparison of the Scorpion x445 & x500. The x500 is considerably smaller at 37.86x14.5x9.39 (Top: x445, Bottom: x500).


Note the orange comm wire for future expansion use :-






Even the sensor connector for the x500 is smaller (Top: x500, Bottom: x445)





As I only installed it for a Pulse emulation, the only sensor I put in was the angle toggle switch that senses the gear position. Note that to install the hop sensor, you'll also need to install the bolt or the charging handle sensor (those two sensors work together).




At least for me, this is the hardest part to install especially trying to find the right epoxy. PsyphyerVII includes a paper cutout template guide on where to install sensor, but I found I've botched up two sensor installations already and had to source these Angle Toggle Switches myself. I'd recommend sticking the sensor temporarily and spin the sector gear checking with a multimeter. Once you're happy with that position, then install it permanently.




Trigger wires soldered :-




My x500 is front wired on the ACR and there's lots of wires coming out of the GBB (2xmotor, 2xgear, 2xtrigger) and there's little room in the receiver to accommodate all these wires. I'm squeezing the wires where I can.



My setup is basically :-

1) Seigetek GS-R 14:1 gear ratio

2) Planet AE1000+ motor

3) 7.4V 1400mAh 30C Lipo


This thing is simply awesome! Possibly due to it being installed on the PTS ACR with a micro trigger, the response is simply instantaneous. There is no lag or delay at all, trigger pulls are very crisp. I also have the x445 installed on my SCAR and the trigger pull for that is also very quick.


In term of functionality, I found it to perform almost as described. I've got all the features (as a Pulse) working except for the the pre-cock feature.


A note, from x445 to the x500, PsyphyerVII has reversed the toggle settings, PM me for more info if required.


Battery voltage checks (switches 1 - 2)

Using the toggle switches you can set :-


Off-Off - NiMH

Off - On - 2-cell Lipo (i.e. 7.4V)

On - Off - 3-cell Lipo (i.e. 11.1V)

On - On - 4-cell Lipo (ie. 14.8V)


I don't have a 14.8V Lipo but the voltage sensors for the others work fine. The gun will stop firing, and an LED on the FET flashes red.


RoF setting (switches 3 - 4)

Settings are :-


Off - Off - RoF at maximum

Off - On - RoF at 20/sec

On - Off - RoF at 15/sec

On - On - RoF at 10/sec


Although I didn't measure it exactly, did slow down with each setting. In Pulse/Scorpion mode, the gear sensor measures/counts it. However in Sentry mode, it's adaptive RoF to PWM reducing speeds to 85%, 70% & 55% respectively.


Burst settings (switches 5 - 6)

This controls the burst options :-


Off - Off - Safe/Semi/Full

Off - On - Safe/Semi/3-round

On - Off - Safe/3-round/Full

On - On - Safe/Semi/Semi-Precock


The first 3 works as advertised and very reliably. Again, the gear sensor at work here. However I couldn't seem to get the Semi-Precock to work, it seems to do a 2-round burst. The nozzle isn't always at the retracted position meaning I'm not always getting a pre-cock setting.


In Sentry mode, since the gear sensor is not utilised, it's time based instead. This requires a calibration setup. As per instructions, when burst is enabled or when the battery is replaced whilst in burst mode, the first 3 shots must be in semi, and the 4th semi shot will be burst. Thereafter it's set and it works as above quite reliably too.


Model Emulation (switches 7 - 8)

These settings allow the Scorpion to emulate back down to Pulse or Sentry. Why would you like to do this? Well if any of the sensors fail during a Scorpion setting, you'll be out of a game for the rest of the day. However, putting down to Pulse disables the use of certain sensors, and Sentry would disable all sensors (and you'll have a regular FET).


Off - Off - Bolt catch dryfire reset

Off - On - Bolt handle dryfire reset

On - Off - Pulse downgrade

On - On - Sentry downgrade


Both first 2 settings require the hop sensor to be installed. For the 1st setting, the bolt catch sensor needs to be installed too. When the hop sensor realises there's no BB in the chamber, the Scorpion x500 will prevent dryfiring. You have to hit the bolt sensor to reset (signifying you've changed your magazine), before you can start firing again.


Similarly for the 2nd setting it's the bolt/charging handle that till signify a magazine change. I'm going to guess why PsyphyerVII included two options here is that some AEGs have an awkward positioning bolt catch (like the ACR, or G36C, etc.). So you can use the bolt handle sensor in such cases instead.


For the 3rd setting of Pulse emulation, this is the one I've been using as default. This disables the bolt/hop sensors altogether and uses only the gear sensor. In this setting one can dryfire.


And finally for the 4th setting of Sentry emulation, all sensors are disabled and the FET performs as a regular AB-FET. However it can do Burst, adaptive RoF, and Lipo protection.


One new feature change from the x445 to x500 that I like is the auto disabling of the AB-FET. With the x445, I had encountered that excessive frequent use of semi-auto, the x445 would heat up and thermal mgt kicks in stopping firing for approx 10 seconds to cool down.


The x500 is now able to disable that auto-temp cutoff in such situations and allow firing to continue. This has worked as advertised. However, I'm not certain how it'll detect other overheating cases and continue to apply the temp cutoff circuitry.


The x500 also has a cooler AB setting and I've noticed that overall it has been cooler (some heat still noticeable but much less).


Untested features

As mentioned above, I've not installed the hop and bolt sensors yet as I'm not certain how to do it for the ACR. Note that there's quite a few things to test under this setting.


Aside from whether it stops firing on an empty chamber, and requiring the bolt sensors to be triggered, there's also the burst reset feature to be tested. Conceptually, in burst mode, if you run out of BBs in the middle of burst, upon mag reload, the burst should reset too.



This is probably my favourite of all FETs. It does everything a regular FET does plus more. And majority of the additional features do work as advertised. I do need to work out what's going on with the pre-cock though.


The gear sensor really is a key to a lot of features of the FET - the full cycle completion, the burst counts, the accurate the RoF control, etc.


I'll need to do more durability tests on the x500 as with the x445 I had the temp sensor cutting out on me in the middle of games.

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  • 5 weeks later...

Mod Edit: Merged


http://www.awsairsoft.com/scorpion Details here...


Got back from overseas, and it was on my doorstep! (well, someone had brought it inside, as it would have got wet!)


All the parts are there, should be fitting it in the next week or so. Looks like routing all the wiring is going to be fun- the lr300 it's going into doesn't have much space to run wires, not like an AK or SCAR.

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  • 2 weeks later...

Well, after some trail fitting, I can say that anyone trying to fit this to a front wired AR15 should consider long & hard before buying! As this is going into a LR300 with a foldy stock, putting it all into the buffer tube is not an option. Time to break out the dremel & enlarge the wiring pass-thru infront of the hop!

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  • 3 weeks later...
  • 2 weeks later...

I'm using the standard Marui version 2 mechbox which came with the gun. However I'm rear wiring it like an M16 to fit the battery into the stock instead of the handguard.


In total I'm squeezing 4 wires through, motor positive, motor negative and the two trigger switch wires, which are very thin!


The motor wires supplied by AWS are quite thick, I might need to buy some thinner wires to go to the motor in order to fit them inside the mechbox.

However I'm quite lazy and would sooner just drop a system revolution into the marui body! =)

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I have the older Scorpion X445 installed in my VFC SCAR-L rear wired. Didn't have any problems squeezing the motor wires, angle toggle switch wires & trigger wires to the back. I don't think the x445 wires are any thinner than the x500's and think in terms of space, the VFC mechbox shell has just as much (or little!) space as the Marui V2.


As an OT about the Systema Revolution GB, check out what batteries you use. I broke the piston rack teeth with a 10.8V 1400mAh & they're not cheap to replace.

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I dont think mine is an X500, I think mine is actually an X445.


I'm really losing patience with it, just found out the angle toggle switch is ever so slightly out of position as I tested it with a multimeter and there is no continuity when the switch is flicked by the tooth, so that will need re-fixing with some epoxy!


Also regarding the Systema Revolution, I'm sure they recommend 9.6V anyway

Edited by JackD
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So far after 4xinstallations (2x445 and 2x500), I have a 50/50 chance of getting that Angle Toggle switch installed correctly. Marking the position isn't the problem for me but it's the epoxying. I've tried different types and the only one which works are the high viscous type (which unfortunately can also seep into the switch and damage it permanently. Luckily I found a place which would sell small quantities of them (at an obscene price unfortunately).


I actually temporarily stick the toggle switch first, put in the sector gear, then hook it up to a multimeter and spin the sector gear. If I get a connection then I know I have the right position, then etch that position on the mechbox.


Actually for anyone buying the Pulses and Scorpion, I recommend buying spare angle toggle switches along with your order. These switches aren't easy to buy in small quantities. I think digikey sells them in batches of thousands only.


P.S. Once you have the Scorpion installed correctly, it's a great FET!

Edited by AnakChan
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  • 2 weeks later...

It's official, I have lost the will to live!


Today I installed everything, tested it half assembled and it fired an worked brilliant!

I soldered the deans connectors on, tidied up the wiring and assembled the gun, tested a few times dry firing to find that it was completing cycles perfectly. I could also see the tracer illuminating which looked awesome, you would even get a bit of muzzle flash if sighting directly down the barrell! =)


However, the problems began to arise when I inserted a mag full of BBs to give it a test shot. The gun fired a few shots then began to misfire, seemed like feeding problems.

I diassembled everything and found the nozzle was jammed, so I split the gearbox in half. Postive wire which loops over the motor shaft (rear wired) was damaged and the tappet plate just seemed to bend rather than retract. Fitted a new tappet plate, insulated damaged wire.

Now the motor will continously run when the battery is plugged in, regardless of whether the trigger is pulled! I can even unplug the trigger switch and all the sensors from the controller unit and the motor will still run continuously aslong as the battery is plugged in!


I assume the controller is buggered!

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Sorry, due to all the events in Japan, I've not had a chance to focus on Arnies. I've got a few recommendations :-


1) get a multimeter and do end-to-end tests of wires just to make sure nothing else got broken.

2) switch the FET to the most basic mode (e.g. emulate Sentry mode, etc.) and work via process of elimination on where the broken part is


I take it that you didn't have any fault in the initial installation? I know I did something silly with my 1st (beta? prod?) X500 where I put the batteries where the motor wires were supposed to be - that was enough to partially damage the circuitry...it still worked but only under some modes it wasn't functioning properly.

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  • 2 weeks later...

Hi AnakChan,

I'm sorry to hear about the disaster in Japan, I hope you are not one of those who lost everything. I must say it saddens me to see your country in such a poor state, when I have been there and seen for myself how beautiful it can be when I visted in 2007.


I'm amazed you have been online at all to be honest mate!

I have already checked with a multimeter (I'm a vehicle technician by trade so natural response to electrical problems) I know the wiring is ok and I've played about with all the settings, I think one of the mosfets has failed and it has permanently switched the motor to live.

I have since taken an old d-boys mechbox I had lying around and fitted a ASCU, which has been impressive so far, but I think a combination of the HRC and the ASCU would be the ultimate solution.



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