Qev + slide valve.

[warhead052]

Heres my plan, I am going to buy a 1/8" qev and a 1/8" slide valve from mcmaster. I need some help with the planning of the rifle though. I would like to get an airsoft bb to fly at least 100 feet, with a minimum of 200fps. I need some help calculating the size chamber I need, the pressure, and the length of the barrel. I would use ggdt, but it won't run on my computer, and I am done messing with it. Any help would be appreciated.

My plans for what I want it to eventually look like, either a barret m82 or a Cheytec Intervention. Air tank storage would probably be built into the gun, but if it is required to be external thats fine. I would like it to last at least 4 accurate shots, but more shots just a little less accurate is ok. A co2 fire extinguisher is my plan for an air tank, so I can charge it to 200 psi and not feel like its going to blow up on me.

Thanks for your help.

[Lockednloaded]

Well you'll need to include some details like barrel ID, and the volume of your FE tank, but just from some assumptions, you could easily achieve <200fps with a small chamber and low pressure. It doesn't take much to get those BBs going

[warhead052]

Barrel id would be as close to 6mm as I could get at lowes or home depot. So I am guessing around 6.4mm? And the FE tank volume would be, give or take, about 1 gallon empty.

[Goats spudz]

you can use something like this http://www.ebay.co.uk/itm/homebrew-pres ... 760wt_1139 for a tank like what im using but you have to use a special adapter or drill out the poppet in the valve or remove the valve

[Gun Freak]

Just hook a blowgun up to the barrel and use a tee mag, with decent pressure they will go fast. You could also use a detent to get higher fps. My detent airsoft sniper can get up to 750 fps and beyond with just a detent.

[warhead052]

What pressure was that at gun freak?

[Gun Freak]

Only about 100, my gun is full metal and capable of whatever I can put in it, but I won't go any higher than about 120 in a match.

[warhead052]

Is your detent sniper on spudfiles? And can you give me some more of the specs on it?

[Gun Freak]

PM me about it

[warhead052]

Alright, I will.