SpudFiles

so iwas thinking i would remake my immense 5ft airsoft shotgun in to a more compact thing to run of my backpack tank. the backpack tank is about 5 ft of 2 in pipe and will be fed through a 1/4 in hose. i'm wondering if i should choke the 1/4 in flow to 1/8 in before it gets to the firing chamber of the shotgun.

not sure on a breech system or if to choke flow to 1/8 from the tank as i won't to be able to get at least 5 shots of of it.

basically the same concept as my other one which is located here...
http://www.spudfiles.com/forums/break-b ... 21558.html

LOL that diagram is terrible. And whats wrong with the current setup? It is already repeating... and you didn't discuss chopping it up with me, hehe. Anyway, choking the flow would only make it fill slower. If you want to limit it to lower air loss out the valve when you open it, 1/8th inch won't be enough. The only way to do it would be put a piston valve or sprinkler on it so it can close quickly. A ball valve will waste too much air if there isn't like a needle valve or something, which will slow down the fill speed.

Here is the tank, for those who haven't seen it. Total length is 64 inches, which is over 5 feet.

what is a needle valve? the other is WAY to big for what a shotgun is used for. cqb. this will hopefully be less than 3 feet depending on how long i should make the barrel.

Well, I think it is a valve that limits flow a lot, down to a very slow rate. hehe, I think thats what it is.
What you need is a 1/2" porting piston valve. You can make one for 5 bucks. Switch up the layout a bit and you can make it ergonomic and powerful. Loads more powerful than a ball valve. Have the hose run to the pilot side and use a three way or fill it from the chamber side and make an EQ port in the piston. This is of course less efficient (you can't use a check valve) but far simpler than using a three way and a check valved piston. I can help you out with it if you are serious about doing it.

Edit, dangit, you edited your post, lol. This cannon can easily be made 3 feet long using a short barrel. You can use a 3 foot barrel with and over under configuration or a 2 foot barrel using the chamber as a stock. I can draw it up if you want.

idk about that. it sounds overly complicated. i'll prb put a needle valve(?) in or something

Not overcomplicated at all, but I have made several piston valve and you haven't made any. I'll gladly build it for you. Be right back with some layouts.

Edit, check these out, there are endless options but ehre are two easy ones with pretty good flow.

mayybe a spring loaded BV but i'm not to sure how those are rigged. they sound simple enough. it would be a great help if somebody could provide a diagram or something

Edited last post with drawings.

Spring loaded ball valves are good, but they stay open and would waste a lot of air. The way to go is a piston valve.

if i pilot it with a ball valve it'll be the same result as using a ball vlave for the trigger becaseu all the air will go throught the path of least resistance which would be out the ball valve. what are you thinking for a pilot because i already said i didn't want a sprinkler.

i don't really like the look of those either. they look identical to the other one. then i would just cut that one in half and voila! they look awkward to hold as well.

Ok, here I am thinking you knew how a piston valve worked.... sheesh.
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One design had a stock, the other didn't. Out of the bottom of the valve, how about and elbow that faces you, then some pipe, then a tee, like I did here.

ok i'm not retarded. i'm just saying that if you open a BV pilot it would be the same result as using one for a trigger. i'm assuming your saying this because you did not see that i didn't want to use a sprinkler valve piloted by a blowgun. this is meant to be a cheap project costing less than 15 bucks. think about it assuming i'm using a ball valve pilot!!!

reedfe wrote:if you open a BV pilot it would be the same result as using one for a trigger.

Not even close. A schrader valve pilot could out perform a ball valve.