Where to start: Pneumatic Airsoft Gun

[BeaverRat]

Hello,
As of now I have made a 2 inch piston valve cannon, and a 3/4 inch sprinkler cannon, but recently I have had the urge to make a small caliber rifle. Airsoft bb's (6mm) sounds about right, and they are cheap and plentyful.

Basically, I want it to be a semi auto gun (not sure at all how that works), probably with a 1/4th inch QEV. I have an old rifle which I can salvage the barrel and other parts from. I will probably run it in the 250 PSI range with a shock pump. I am really at a loss as to where to start on this one. I couldn't find much info on it by searching.

Anyway, are there any links, tutorials, or other guns that I can use as a reference in building my own?

Thanks

[Crna Legija]

Go with 3way+QEV with a cylinders to load ammo. Its the easyest way i think. Just like POLAND_SPUD did

[jackssmirkingrevenge]

You can also pilot the QEV with a pop-off valve for full auto, as well as modding the QEV for chamber feeding which will give you better efficiency, though if you use a 3-way pilot it's not an issue.

[lemming124]

hammer valve might be simpler for a semi?
http://www.spudfiles.com/forums/p-4-bb- ... 12216.html

[Crna Legija]

idk, its pretty easy to screw a 3way valve into a qev and connect to air supply.

[spudtyrrant]

idk, its pretty easy to screw a 3way valve into a qev and connect to air supply.

his "air supply" is a shock pump i agree a hammer valve might be more appropriate for his situation.

[jor2daje]

ya spudytyrrants right, if hes using a shock pump hes probably going to want something really efficient. However I would recommend against using the shock pump for semi auto, 120 from a compressor does plenty of damage for semi auto, and what it lacks in individual power it makes up for with shear volume.

I think the shock pump is best suited for a high power, small bore, single shot cannon.

[BeaverRat]

Ok, I am convinced... It will still be a semi auto, but it will have an onboard reservoir filled to about 150 PSI. If I were to use a 3 way and a QEV, I would have two reservoirs right? One that is used for firing, and one used for refilling the firing one. When I trigger the three way, it shuts off the passage from the big reservoir to the small, this allows multipe shots...

Did I get that right?

[Gun Freak]

Use a big HP tank connected to a blowgun with a tee mag in front of it, and shizam, semi auto.

[BeaverRat]

I believe I understand how to achieve semi auto firing, I just don't get how to have semi auto BB loading.

[Gun Freak]

Use a tee mag with a detent in front so it doesn't double feed. You don't really need a cylinder or BFB or anything.

[Lockednloaded]

well this is a good example of a normal airsoft gun power pneumatic. Jack didn't like it because it was lacking in power, but for a gun to use in skirmishes; this would be a good build

[jor2daje]

heres my qev 3way valve and cylinder gun, it uses the pneumatic cylinder as a bolt, you can see the diagrams I drew to explain this a little better in the thread.

I would agree that a bfb bolt in theory is easier, but having built both, I think that the cycling rate of a bfb is slower and its actually more difficult to build an efficient one.

[BeaverRat]

Thanks guys... Does anyone have a picture of the mcmaster 1/4th inch QEV? I think I will use that, if it is not too big.

http://www.mcmaster.com/# Product ID: 6646K32

[maklaw]

Hello, my name is Fran and I first congratulate you for this great forum.

The other day I went to play paintball with friends and seeing weapons manufacture a thought.
You had everything thought out and went to buy a QEV + pop-off but the salesman told me that the QEV shoot some pressure alone, is this true??

Shoot only QEV? to pressure?

Sorry my English

Greetings