STD M1911 (CS007/009) Dive in and Mods

Thats a great tip @Cruise I did smooth off the spring but perhaps I should glue a washer or something inside the piston head to take the brunt of where the spring meets it.

A Drawing of the pistonhead mod would be awesome if you would track it down! I can see how the gearbox would be out under punishment, I was thinking of leaving the 3 cell lipo mod out (even though I am tempted :wink:) it appears to make the gears work a lot harder/faster.

The barell mod is interesting, you mentioned going down to a 7.1 or 7. is that the internal diameter? I imagine it would be worth going to aluminium if doing this? Do you mean that you require hardened gels with this mod when you refer to “usable gel hardness”?

A washer is helpful.
Be mindful of the weight and use teflon tap washers cut to size if you use a few.

I prefer 7.1 or less in pistols and short barrels. More fps. M92 and G18 are 7.0 ID stock.

You need to stay with medium hardness when going tight barrel (tricky these days when everything is labelled as hard, hardened or hardest)… They hit hard enough at 10m or less. So I use WI Reds and milkies, at least until they change the formula.
AKAs and Ultras and gels with larger ave grown sizes like AT yellows will jam in a tight barrel.

Have a look at for hop ups.
Innovative products, well-priced and responsive.


Just ordered me some of them silicon air nozzles👍


Grinding a flat surface on the middle post is straightforward.

How much you grind depends on the height with the original rubber cup fitted minus the thickness of the nylon/teflon plate used.

It is a bit of a juggle because too thick a plate can leave too little clearance for the o-ring which needs to be slightly loose. I find 2mm teflon sheets work well.

This is necessary to not affect the AOE at the pick-up tooth on the piston ladder.
The diameter of the plate is not crucial so long as it is about the same as the piston itself.
The compression seal needed is between the ring, the piston body and the cylinder wall.

As these pistons were designed for rubber cups, the gap between piston and cylinder varies. Do make sure the o-ring is not so thin that it can slip into the gap.


Oh yeah!
Cheers for that cruise👍
That is way simpler than what I imagined, and can be applied to so many other units that don’t have the commercial upgrade options available.

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BTW, I have the Tomahawk hop up on a stock CS009 and after tuning it sends gels level and accurately past 20m.
So I’m a fan. :sunglasses:

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Hi all, great info here.
Does anyone have a photo of the gear alignment for this gearbox by any chance?
Thanks in advance.

What do you mean by gear alignment?

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Well it was my first pull apart, (a lot of hiccups involved). As I opened the gearbox everything had basically sprung apart so I wasn’t sure how the piston/plunger aligned on the last gear (one tooth to the left or first tooth in the first “gap”). I ended up figuring it out, Although I HD another issue where the first gear after the motor would disengage after firing and wouldn’t actually turn the gears. Is that a common issue ? I managed to fix it with a small washer/spacer sitting atop of the gear. All firing again now. :+1:t2:

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Glad you got it sorted.
No, gears not engaging is not common. I’ve opened many of these and similar gearboxes.

I often forget precautions I take when opening these things. From memory and this may help you if there is a next time,

  • If possible, cycle the blaster till the spring is the least compressed
  • I then use a flat piece of metal to hold the main cylinder down via the slide slot as I separate the shells.
  • Alternatively, I hold down the barrel and tpiece. It keeps the nozzle in place which in turn stops the main cylinder from tilting up to allow the spring to pop out.
  • With some, I drill a hole through the rear of the gearbox into the spring retainer. This allows me to insert a rod/screwdriver into the spring retainer again preventing the spring from popping out.

Just my luck then hey ! Lol.
Yea I managed to use a small flat blade to hold the cylinder down as I put it back together.
I can also see how drilling a hole in the back of the casing would help a lot too!
Where would you recommend packing out the spring ? And by how much ? (Stock spring).

Also, Would you say that’d be the most you load you could put on the stock motor/trigger switch before needing to upgrade them.

Difficult to comment on packing as I lifted the fps on this by using longer and stronger springs instead.
On other pistols, I have packed up to 8mm.

Do it in small steps. It’s tedious as you have to reassemble the gearbox each time to reach the spring. Fortunately, gears and gearboxes are available and cheap.

Bear in mind I also used a tighter barrel, modified the pistonhead and used a silicon nozzle.

I later upgraded the motor while downgrading the spring. At 195-200fps it was sounding like something would soon break.

Motor I upgrade when I hear it give up against a stronger spring or when the battery gives up much earlier than before. At $4-8 each, it’s a no-brainer. I had to do some dremeling but these days drop-ins are available.


Fairenough. Sounds like you know these things back to front !
I appreciate all the info and knowledge. :+1:t2:

As the only decent albeit hopperfed AEG pistol I did give it more attention than others.
Despite it’s shortcomings, it was still the electric sidearm with higher rps than most and with little or no lag.

That gearbox is robust.
I have not had a gear strip despite all the torture I subjected it to. That made it a fun experimental platform.
I think most of the screws on the magfed conversion are 0.5mm thicker and a mm or 2 longer because I’d opened it so many times. Just keeps on ticking.

Have fun.


Thanks for all of your help @Cruise! I will send in an update once I finish attempting the piston mod and get a fps reading for my CS-009. It’s starting to look like the pistol from Robocop with my jiffy box extention so that it can fit turnigy lipos :wink:


Even better. Look forward to it. :+1:

The concept M1911s take a step closer to reality. :sunglasses:


6mm auto Gel Blaster
Had a spare M1911 gearbox so… decided to modify to suit 6mm gels, chuck it in a shell and see.
Stock gearbox + 6mm x 14 S/S barrel with tpiece and hopper modified to suit.
180fps accurate to 15m. Hmm…
200fps with 1cm longer 1.1 spring. Flat past 20m.
215fps with the hard stuff.
Respectable numbers from a $69 AEG :sunglasses:

For some reason it’s quieter too. Piston probably slows down faster with the air resistance.
Will try chamfering the cylinderhead to assist airflow.

There are no 6mm gel hop ups but the twin blade one from Tomahawk still increased usable range with 50-75cm spread to 25m.
Not for the hard stuff though, they’d just destroy a hop up.

Going to try growing some 6mm gels in Tintex Fluorescein. Frankly, I’m sceptical as molecular size becomes an issue, but if it works, I’ll have a 200fps 6mm glow gel pistol.
Can’t hurt to try. :sunglasses:


I’m keen to see your results with Flourescein! I have a bucket of the powder at work. That stuff makes EVERYTHING nuclear glow.

How will you have it glow? UV LED in the torch?
I dont know if it holds a light charge or is just reactive to the UV whilst it is being lit up.

Good point. Will have to wait and see.
I’ve put a UV LED in the feed tube just before the tpiece.