Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 66 users online :: 6 registered, 0 hidden and 60 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], MCRKilljoy, MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Simple coaxial BB handgun

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
Sponsored 
  • Author
    Message

Simple coaxial BB handgun

Unread postAuthor: SpudBlaster15 » Sun Aug 19, 2007 12:53 pm

I built this gun because Tylerthetatertosser built a similar launcher, and I noticed several ways in which it could be improved.

This launcher is designed to be operated as a handgun as the last picture shows. It is rather powerful, outperforming my Crosman 2100 air rifle at 180psi. Not bad for $20. I would like to take it to higher pressures, but I do not weigh enough (145lbs) to force the bike pump to complete another stroke.

Specifications
Chamber: 30" of 1/2" type M copper pipe
Barrel: 30" of 1/4" steel brake line (inside diameter ~.185")
Piston: Cast hot glue, 1/4" in length, 1.5 grams, rubber sealing face
Piston seat: Flared end of 1/4" brake line, .3" in diameter
Piston travel: 1/8"
Pilot valve: Modded blowgun (taken from my pneumatic paintball gun)
Pipe bonding: Epoxy (JSR will like this one :D )
Maximum pressure used: 180psi
Maximum pressure planned to use: 250 - 300psi

The blowgun valve needs new o-rings, as the current ones do not fit on the piston tightly enough, and at pressures in excess of 150psi, they are ripped out of place by the high velocity air moving over them.

Pictures

The whole launcher:

Image

Focussed on the piston assembly/pilot volume:

Image

Firing position (yes it is raining outside):

Image

Thanks for viewing.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: spud yeti » Sun Aug 19, 2007 1:17 pm

Looks like a really nice little gun there. I must commend its abilities too, especially for the low cost. I like its simple look, even though its got (comparitively) great performance.
Good work
  • 0

really good quote/phrase here
User avatar
spud yeti
Brigadier General
Brigadier General
 
Posts: 1030
Joined: Tue May 08, 2007 1:41 pm
Location: Cape town south africa
Reputation: 0

Unread postAuthor: potatoflinger » Sun Aug 19, 2007 2:32 pm

That looks pretty cool, I might have to build one, since I found a few schrader valves on the ground in the auto parts store parking lot. :D (And I need a new project)
  • 0

It's hard to soar with eagles when you're working with turkeys.
User avatar
potatoflinger
Brigadier General
Brigadier General
 
Posts: 1136
Joined: Thu Nov 02, 2006 3:26 pm
Location: Maryland
Reputation: 1

Unread postAuthor: Skywalker » Sun Aug 19, 2007 2:52 pm

Hah! I couldn't figure out where the chamber was because it looked like a barrel-sealing Tee piston, and then I remembered that it was a coax! :lol:


Looks nice. Do you like the hot-glue piston? Sounds like it should be easy to make, and maybe at that size it would hold up ok. You ought to make a wooden stock for it, that would be cool. It'd be hard not to cover up the schrader though... hmm. :?
  • 0

User avatar
Skywalker
Sergeant Major
Sergeant Major
 
Posts: 177
Joined: Sun Aug 05, 2007 7:22 pm
Reputation: 0

Unread postAuthor: SpudBlaster15 » Sun Aug 19, 2007 3:01 pm

Thanks for the comments so far.

The hot glue piston works well, and was used simply because it was quick and easy to make. Simply plug in a hot glue gun, apply grease to your mold, then fill it and let it cool. Once it is cool, the piston pops out of the mold with minimal force. Use CA glue to attach a piece of rubber to the front, and your done. The whole process, including waiting for the glue gun to heat up and the casting to solidify, takes about 10 minutes. The internal barrel supports are also made of hot glue, cast using the same process. The entire gun build took less than an hour.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: bassmaster1228 » Sun Aug 19, 2007 3:18 pm

hmmmmm hot glue piston... i like i like
  • 0

current project: portable pnuematic sniper rifle

bassmaster1228
Specialist
Specialist
 
Posts: 42
Joined: Sun Jun 17, 2007 6:51 pm
Location: Mobile, Alabama
Reputation: 0

Unread postAuthor: Hawkeye » Sun Aug 19, 2007 3:36 pm

You need to learn how to bounce your weight slightly on your bike pump handle. If it is a high pressure pump designed to go to say 160psi you can get it to max out at least , even if you are a lightweight.
  • 0


Hawkeye
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 462
Joined: Sun Jan 21, 2007 7:12 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: SpudBlaster15 » Sun Aug 19, 2007 4:19 pm

I managed to get it to 190psi just now - 30psi over the pump's rating. If I bounced anymore on the handle, I think it would bend.

At 190psi, a steel BB will go through both sides of a paint can.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: f.c » Mon Aug 20, 2007 5:34 am

loverly wait till i show everyone on here the power of my new strafer its gonna blow you all away.
  • 0

User avatar
f.c
Captain
Captain
 
Posts: 340
Joined: Sun Jul 08, 2007 2:40 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Mon Aug 20, 2007 5:39 am

Pipe bonding: Epoxy (JSR will like this one)


:notworthy:

hehe

Nicely done, though I do recommend you ditch the blowgun, actuate with the schrader and take it to 300 psi or more with a shock pump if you really want to see performance improve.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: SpudBlaster15 » Mon Aug 20, 2007 11:43 am

I attempted to actuate the piston with the schrader, but the pilot volume is much too large in it's current configuration. I suppose if I ditched the T, and attached the schrader directly to the brass fitting, it would most likely actuate.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Re: Simple coaxial BB handgun

Unread postAuthor: Hailfire753 » Mon Aug 20, 2007 12:30 pm

SpudBlaster15 wrote:I built this gun because Tylerthetatertosser built a similar launcher, and I noticed several ways in which it could be improved.


Geez, you guys must have some kind of rivalry or something! Anyways, great gun!
  • 0

UPDATED MARCH '08
field-legal paintball semi
User avatar
Hailfire753
Captain
Captain
 
Posts: 348
Joined: Thu Jun 28, 2007 11:50 pm
Location: Near Philadelphia, PA
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Mon Aug 20, 2007 12:40 pm

SpudBlaster15 wrote:I attempted to actuate the piston with the schrader, but the pilot volume is much too large in it's current configuration. I suppose if I ditched the T, and attached the schrader directly to the brass fitting, it would most likely actuate.


Yep, you need a tiny volume for effective actuation with a schrader - the largest piston I triggered with such a system was on my 3/4" launcher, it was 1 inch diameter but with a pilot volume of only 0.15 cubic inches.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: SpudBlaster15 » Mon Aug 20, 2007 1:04 pm

56 grams of gelatin + 350 milliliters of water = homemade ballistics gel.

Crosman 2100 BB gun at 10 pumps - 2" penetration.

Coaxial BB gun at 50psi - 1" penetration

Coaxial BB gun at 80psi - 1.75" penetration

Coaxial BB gun at 100psi - 2" penetration

Coaxial BB at 180psi - 3.25" penetration

Image

Geez, you guys must have some kind of rivalry or something!


Its not so much a rivalry as a generation of ideas through combined thinking.
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: joannaardway » Mon Aug 20, 2007 2:15 pm

That's a nice photo of the BBs in the gel - it would be much better if it were slightly more in focus though.
Nice BB launcher. I don't do enough in either the really small bores or bores above about 1", and I should really do more.

I feel your pain when you're on about the pump limits. I've actually bent my pump shaft trying to get some more pressure out of it. Even at 155 lbs in weight , I have difficulty getting above 200 psi with the pump I have.

Actually, the pumps on the market have actually irritated Ragnarok so much he's building his own 300+ psi track pump from copper pipe, specially ordered parts, and some PVC rod and sheet. I think I'll be borrowing that when he's done. (But don't tell him!)
  • 0

Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
User avatar
joannaardway
Brigadier General
Brigadier General
 
Posts: 949
Joined: Mon Oct 09, 2006 4:57 pm
Location: SW Hertfordshire, England, UK.
Reputation: 0

Next

Return to Pneumatic Cannon Database

Who is online

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], MCRKilljoy, MSNbot Media, Yahoo [Bot]

Reputation System ©'