2.5 foot chamber
2.5 foot barrell

222fps
60PSi

2foot chamber and barrell = 211fps @ 60psi

I was thinking a 3/4 QEV hooked directly to 3/4 pressure washer hose. Long enough to equal 17-20ci. The other end could be the female Quick disconnect end I could plug my airsource into

Well GGDT says if i have 17ci chamber then I need 250psi to get the nerf up to 230fps out of a 14" long 2" barrell

A length of 1" pipe may be easier to aquire. I just thought the hose could fit in the gun better without having to use fittings and 90 deg elbows.

I need a 1" x 10" chamber that can hold up to 300psi.

I had planned on using galvonized steel pipe but thought the high pressure hose would be more compact.

The cannon im building is a replica HK69 that shoots nerf vortex footballs

Im thinking of using pressure washer hose as a chamber for a small cannon im using.

I just dont know anything about them. I want to attach a regulator to the end to fill it from a co2 tank and connect the other end to a valve.

How do I attach fittings to the end.

use it to look at Area 51

I looked on Technobots and thos QEV's should work great.

Price isnt too bad and they also have a 300psi check valve.

Thanks.

Im looking for a valve.

Preferably with an output close to a 3/4 QEV or a 1" sprinkler.
I need it to handle 280 psi at a min.
Id like to keep it small.

Been looking o google with no luck.

OK.

If I put a 10 inch long 1-1.5 in chamber ill get about 10ci chamber.
Ill need a chamber and valve that holds 150psi. Ill also need a way to fill it to that pressure quickly. Im thinking of using a 12 gram co2 quick change hooked to a valve...like those used to fill bike tires.

What id like is ...

Great advice.

Ill probly use a QEV and put the chamber in the forestock.

I may model it off of the HK69 instead and use the grip as chamberspace also along with the reciever section.

hmmm. Also if I use a smaller chamber size the 12 gram generates to much pressure so I need a way to only use part ...

Im working on designing an M79 and need some advice/recomendations.

I want it to look like an M79....not an M14 like the ones online.

I want to shoot nerf footballs....the 2 inch kind.

I have it worked out on GGDT and I need to fit 50 cu inches into the gun somewhere. Any ideas.

Ill get 200 fps ...

I think a 3/4 QEV is a little smaller then a sprinkler....Can anybody confirm because im not sure and asked the same question in another post and got no reply.


ahhh...a 1 in sprinkler should suffice

Hmmm,

The M79 would be difficault to make work because it dosnt have any room for a chamber big enough to fire nerf projectiles (ive been trying to build one for a while).

The mini nerf footballs weigh 26 and have a diameter of 1.98 in

I use a value of 1 psi for friction for a 2 inch pipe.

You ...