SpudFiles

At the moment, I am building my first QEV gun. My current setup is a 3/4in QEV with a 6in long 3/4 chamber and a 1/4in ball valve pilot. I hope to run it at 300psi+ once i get my shock pump. I still haven't decided on a barrel size. Any tips to make it more efficient or input on what barrel would be the best is appreciated

I am almost positive that it will take decades to pump up that size chamber with a shock pump...

Im not so sure...it takes five pumps with a bike pump to get it to 120psi im guess it will ta ke about thirty pumps

I have to agree with BeaverRat, I find anything over 1 cubic inch becomes a bit of a chore with a shock pump, and you have almost 3 cubic inches there.

As to the barrel, calibre depends on what you want to shoot (BBs/marbles/anything in between) and in terms of power and efficiency, the longer the better (assuming barrel volume doesn't exceed volume of air in the chamber at atmospheric pressure)

about ten minutes straight with your average shockie to fire one shot. Get a floor bike pump instead. Many will go 200 psi+ and take a minute to pump up that chamber.

Okay thanks for the input im probably gonna go with a .5in barell then i can use marbles and ball bearings

Here is a high volume and high pressure pump that can push 300 psi.
And here is a smaller volume and cheaper pump that isn't a three stager but for your volume it would suit your needs.
As for barrel size, choose one in which the ammo can be of a constant size and that is cheap and plentiful. Airsoft bb's are a good example however I think you'd want to go with a larger calliber in this case.

I went with a half inch barrel, i used ball bearings i have from some magnetix kits i got a garage sale, i have about 1000 of them now. To fill it i use my friends air compressor and can get 200psi, performance is good, plenty of power but only so-so accuracy because of the smooth bore.

Get a fridge compressor and you can get 500+psi with the flick of a switch, iv had myn too 800psi, someone took his passed 1000psi

Where can one obtain a fridge compressor. I dont have a spare fridge at the moment.

Ahh yes I used those bearings before in a half inch barrel for this gun. They are a little loose but they work.

jim_himself wrote:Where can one obtain a fridge compressor. I dont have a spare fridge at the moment.

you don't, i always keep one in the corner just in case , try a junk yard or look around streets people always throw away old ones.

Well il start the hunt in my local junkyard.

i got 3 from a junkyard just in case one didn't work and it only cost the entrance fee, i had to cut it out my self not hard but its illegal to release the freon in side them, something about the ozone