Cylinder /barrel ratio. Test and results.

Davegolf said:
The Scar barrel is a 6.05 320mm
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Cheers - so it means that 53.5 distance

if we take off 20 in total or so will give perhaps 335 @ on about 2.0:1

or a bit more vol on a slight shorter barrel

or take off a bit more in calculating prior to x10 for higher volume heavier bb's

So even my revised 12 to 15 seems incorrect if you seek a 2:0:1 ratio

15 might be ok for 1.75:1 volume but shooting tests might still not be ideal

(like I said some of the stuff written like 1.47:1 ratio I thought was way too low tbh)

as yourself & Hangtight find a ratio of 2:0:1 upwards better then perhaps the subtraction figure or Y needs to be 20 or a bit more

X = port distance

Y = value to subract (15 for 1.75, 20 for 2.0 or 25 for for 2.25:1)

Z = barrel length

(X - Y) x10 = Z

(kids remember brackets or equation will be wrong as multplication takes priority over addition & crap)

F*ck me my head hurts - this was supposed to simplify it

but as per usual I've made way more complicated than it needs be :D

 
Lol!

Yes I think the lowest ratio that actually performs seeing as this is what people would be considering or calculating this for in the first place is 1.9

Lots of us have arrived at a similar conclusion by our own testing... 

General consensus for AEG's is;

0.20g = circa 2.00:1

0.25g = circa 2.20:1

0.30g = circa 2.30:1

 
I'll do the maths in a bit, but it should be possible to come up with a really simple formula that you just put the BB weight and port position in and the approximate barrel length falls out the other end.

 
So while just randomly looking online I found this handy website (loads of items covered, such as modifications, rebuilds, how-to guides), but at the bottom of the ‘calculations’ page is a volume/barrel ratio calculator - handy for any quick references.

http://airsofttech.dk/Calculator.cshtml

 
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Sev said:
Sorry to necro, but this may be handy for those discussing here, as well as anyone else interested.

I was trying to find ways of calculating this all myself too. I have made a spreadsheet that should do the trick.

https://drive.google.com/open?id=1_ZkGx_l-1dOppvGsG9w7vEiVVOB1CI2co6JkO_1_JtI

Downloadable Excel file: https://www.dropbox.com/s/v6093fxjeme36h1/Volume and BB Weight Calculator by Sev (Excel).xlsx?dl=0
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so much thanks.  though no pressure, this will heavily affect my decision as to what barrel to fit into my SVU

 
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