MEASURE! and don't get your cylinder/barrel ratio wrong like me... = .=

this is intended for people who might make same silly mistake as me,
or those whom are interested to see what each ID size coupled with most common length barrel does in one big chart,
because i been using the forum calculator for my baseline…
and it says length to port is 70mm…
stupid me have assumed it’s actually 70mm of stroke length… :sweat: :sweat: :sweat: :sweat:

today the one piece cylinder came in so i did some measurement,
and learned that the actual effective cylinder travel is only 60mm,
which dropped the ratio by quite a lot…

my original idea with my ACR was for a long barrel + silencer sniper-ish look,
so kinda wanted 400mm inner, with ID of 7.3 - 7.5,
but now if i wanna keep with in that sweet spot (?),
i can only use barrel from 325 - 345mm long depending on ID :sneezing_face:
now i have to re-work out design and shit again to account for shorter inner barrel :expressionless:

do the calculation, and measure shit properly guys,
don’t be like me :hot_face:



Good little spreadsheet though, can I get a copy?

Yah sure o.o!
Pm me a email or something I send it tonight :smiley:

I use a simple spreadsheet too.
Just punch in some numbers and you get an idea of barrel length.

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oh interesting O_O
you listed all the piston travel too

Yes, although the cylinder ID will vary with each blaster and can range from 23.5 to 23.9 and from 18.0 to 19.0.

Just remember barrel length is a guide.
Some plungers leave more dead space than others while barrel tightness also plays a part and varies with each barrel-gel combo. :sunglasses:

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there really is no standardisation when it comes to blaster parts is there :sweat_smile:


That, is half the appeal/frustration depending on your POV. :sunglasses:


I have been doing some work on a CYMA short Mk18 and I reaally need it to be just a bit longer. To reach what I need as the correct size for my project, my inner barrel alone is 35cm. I chat a bit with a friend, some of you may know him as GalaposJ on YouTube and he has around ten years of experience with these Gel Blasters, well him and his mates there. They have their blasters capable of up to 450fps I believe, but that is with a lot of trial and error. So, it might be worth listening to what he has got to say. Anyhow, you used a chart, to explain things, but I think the chart he has might make it even simpler and tell you just what cylinder you will need for optimum performance, per barrel length. Here is a link to the video if you have not already seen it. Many other good tips in there too, worth subscribing for the info alone.

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Yep… every setup’s different. On the fly lateral thinking and improvising’s what I find the most appealing about these hunks of plastic and metal. :+1: