Spring Loaded Paintball Gun

rocketpunch · Mon Dec 28, 2009 12:21 pm

Hello, been reading this forum for quite a time, i really like it, it's a bit overwelming at the beggining but now i feel more confident with spudding hahaha

the reason for this post is that i want to build a paintball gun or rifle, based on the drawings attached, it's way too simple, but i think it will suffice. The problem is that i need to choose a spring and a piston chamber. What do you suggest? The projectiles are .68 regular paintballs, i want at least 150 fps. Also, are there any desing flaws? Is a gravity loader a mistake in this type of gun?
Thanks in advance.

Edit: there's a mistake on stage 2, it's obvious that the spring relaxes hahaha

jackssmirkingrevenge · Mon Dec 28, 2009 12:23 pm

It should work, but it will be a bit awkward to fire, is there a trigger or do you just shoot it like a bow and arrow?

rocketpunch · Mon Dec 28, 2009 12:39 pm

i forgot to draw a little "bite" in the green stick ( i call it "embolo" but don't know how to spell it in english) that fits in the pvc cap. the trigger is simpli pulling up the green stick a little so it escapes the hole and the spring does the rest.
Any suggestions about size?

kjjohn · Mon Dec 28, 2009 12:42 pm

Looks like a big airsoft springer to me, but it should work. You would, of course have to devise a way to cock and fire it. With the right mechanism, this could even be made automatic. I don't think it will reach very high velocities, but you should be able to get at least 150fps, airsoft springers can easily get 200.

In terms of piston size, you should get the piston as big as you can, and use the most powerful spring you can find. More piston surface area=more compression and velocity. If I were you, I would put a check valve going into the chamber, so that when you cock it, it pulls in new air.

Also, you would probably be a lot better off with some kind of sealing mechanism for the breech as well. Otherwise, a lot of the pressure will be lost in the gravity mag.

jackssmirkingrevenge · Mon Dec 28, 2009 12:49 pm

rocketpunch wrote:i forgot to draw a little "bite" in the green stick ( i call it "embolo" but don't know how to spell it in english) that fits in the pvc cap. the trigger is simpli pulling up the green stick a little so it escapes the hole and the spring does the rest.

Ah, you mean like a notch. Makes sense. Also, embolo, es español o italiano?

rocketpunch · Mon Dec 28, 2009 12:55 pm

español, but i believe the term comes from italiano. in other words, the thing that propels the proyectile or stings the igniter

qwerty · Mon Dec 28, 2009 12:57 pm

Yeah, you will need a big, powerful spring for a good amount of fps

I don't think it will reach very high velocities, but you should be able to get at least 150fps, airsoft springers can easily get 200.

But airsoft bb's are so much lighter and smaller i think you're better of with a simble spring loaded BV.

rocketpunch · Mon Dec 28, 2009 1:01 pm

@kjjohn:
i've been searching fora "big bb springer" for paintballs, but with no luck, so i want to prove that it's possible and easy to make.
thanks for the tip about the valve, is there a way to make a homemade valve like that or i need to buy it? i ask that because i have no clue how to calculate the pressure it has to tolerate. I can handle physics (university) but lack of spring information is a problem hahaha

kjjohn · Mon Dec 28, 2009 2:03 pm

A check valve is a valve that only allows air to move through it one way. In your design, it would not have to withstand much pressure, and you could buy one for under $10. McMaster has some for fairly low prices. You could make one yourself, but it would would probably cost more than buying one.

rocketpunch · Mon Dec 28, 2009 2:20 pm

ok i'll see what the hardware store gods have for me. what kind of breech sealing do you suggest? will a spring mag help?

kjjohn · Mon Dec 28, 2009 3:37 pm

I have never created a breech load before, but I would suggest using a sleeve over an opening in the barrel, with o-rings. Take a look at Hubb's barrel guide, it has some good examples. Using a spring mag probably will not make a difference.

In terms of check valves, you probably wont find them in hardware stores, I have never seen any in retail stores. Order one from McMaster, it's only $10: http://www.mcmaster.com/#check-valves/=54rbon

twizi · Mon Dec 28, 2009 3:53 pm

hey look at the airow gun it uses a bow and airrow it shoots paintballs it really cool

rocketpunch · Mon Dec 28, 2009 4:25 pm

thanks for that kjjohn but i don't have a mcmaster here =(
hey twizi, i've seen the airow, does anybody nows the patent number for that? i'd love to see how that's done.

kjjohn · Mon Dec 28, 2009 4:34 pm

too bad about not having McMaster. What country do you live in?
You should be able to find some check valves if you google it.

rocketpunch · Mon Dec 28, 2009 5:01 pm

in Argentina, quite far away from there hahaha.
i thought about mounting the magazine on some kind of rail, to seal the barrel and also have time to pull out the spring withouth the need of a valve. so, to reload, i just pull the magazine, pull de spring, and pull the magazine. a spring on the magazine rail would help also.

update:
i just can't find the way to use a hard spring in an usable way. The way commercial air guns work, with a lever and a spring, is nice, and i will try to implement that.

Spring Loaded Paintball Gun

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