BB/Marble Rifle Design

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
User avatar
DYI
First Sergeant 5
First Sergeant 5
Antigua & Barbuda
Posts: 2862
Joined: Sat Jul 07, 2007 8:18 pm
Location: Here and there

Tue May 13, 2008 3:59 pm

i say go with 1/2" copper for chamber... then a high pressure pump or CO2- speaking of which can copper hold 800 PSI?
A chamber made solely of balsa wood could hold 800 psig if it was thick enough. If, however, what you meant was "can the commonly available Types M or L copper water pipe hold 800 psi?", then the answer is, still, yes. It is over the rating, but still nowhere near the burst pressure for M, and I believe it is actually below the rating for type K.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue May 13, 2008 4:03 pm

cool thanks DYI
"Some say his pet elephant is pink, and that he has no understanding of "PG rated forum". All we know is, he's called JSR. "
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 4:51 pm

Ok people, Listen Up!!!

I have recently decided to change this from a "marble" rifle, to a "bb" rifle because you can reach higher velocity at the same pressure with a bb rather than a marble. Also, one of my bb guns broke and I have a perfectly good 2" long bb-barrel :D It's even rifled!!!

I threaded it externally so it can be exchangeable for different barrels.
everything is working good as far as the piston valve assembly, just need to get some parts welded at school tomorrow.

Ask if you don't get something and I can post a picture or two.
It's coming along :D :D :D Sooo exited!

Oh! I also got a bunch of stuff from the bb gun like a kick ass scope, a stock (kind of crappy so I'm still going with the homemade one), the pump, and some internal stuff (like springs, trigger assembly, etc.).
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 5:40 pm

LOL will a 2 " long barrel fit your needs?your chamber is going to have to be really small lol
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 5:41 pm

I know its pretty short but it should be fine accuracy wise up to.... 50 yards. And I plan on making my chamber smaller so that will help too :wink:
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 5:44 pm

Nice. it will all fit in that stock real nice now. You should make a high pressure three shot burst gun so if accuracy doesn't turn out good, you will have other bbs to compensate :)
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 5:45 pm

FordGtMan wrote:Nice. it will all fit in that stock real nice now. You should make a high pressure three shot burst gun so if accuracy doesn't turn out good, you will have other bbs to compensate :)
lol, maybe...I'm thinking about doing the high-pressure pump. I have all the supplies I need....

IDK, we'll see :wink: :?
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 5:53 pm

So you are actually considering just having this gun used at 120 psi? It just wont be nearly to its full potential... :(
Lets make that "maybe" a "DEFIANTLY"
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 5:59 pm

lol, i know, that's why I'm debating whether or not to use the high-pressure pump.

You see, here are the arguments:

+compressor: Easy/faster fill up
-compressor: Low psi, long to start-up and not portable

+HP pump: higher pressures and portable
-HP pump: Long...everything

But all-in-all, I think the High Pressure pump is a winner, So attention everybody, I WILL BE USING A HIGH-PRESSURE PUMP!!! lol, I just shouted that and my mom was like, "Who the hell are you talking to?". lol :wink:
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 6:01 pm

Hopefully she doesn't think you are talking to your girlfriend... :D If the chamber is going to be small as hell anyways, it wont take long at all to fill it right? How big of a chamber are you going to use?
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 6:04 pm

lol, no...not my girlfriend :oops:

um, for the chamber, I was thinking 1/2" copper pipe. About....eh...6-8" long.

What do you recommend? I would like to keep it below 9 but don't want it to be too long for pressurizing time purposes...
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 6:07 pm

Dont think it would even matter much even if it was under 5 inches cause it would still be like a 15:1 ratio...lol :D
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
STHORNE
Sergeant 3
Sergeant 3
Posts: 1208
Joined: Wed Feb 14, 2007 7:50 pm
Location: Kewaunee, Wisconsin

Donating Members

Thu May 15, 2008 6:11 pm

lol, true. but it's all about powa. THE POWA!!! :director: :violent3: lol
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
User avatar
FordGtMan
Specialist 3
Specialist 3
Posts: 314
Joined: Thu Oct 25, 2007 9:15 pm
Location: southlake Tx

Thu May 15, 2008 6:18 pm

Lol, i think you should just invest with a longer bb barrel and then use the 2" for a covert mini coaxial :). Only with extremely high pressure will you be getting power with a 2 " barrel. I mean, co2 guns use 800 psi and most only get around 400 fps, or are they regulated down a bit? either way, i say the longer barrel. :( :roll:
People call me ThunderChunks...I dont even know why...
Got a Gamertag?, mines KillerHedgeHog3, add me :)
User avatar
bigbob12345
Staff Sergeant
Staff Sergeant
Posts: 1516
Joined: Sat Dec 01, 2007 9:13 am
Location: Mercer Island,Washington

Thu May 15, 2008 6:20 pm

High pressure pumps do have disadvantages, many of them
1. They can be tricky to build depending on your exceperience with things like that
2. They are costly(ussually $60+, but i managed mine for about $50)
3. It takes a really long time to fill anywhere near a sizable chamber
4. If not made well they can be very unreliable and have a tendency to break(So make it servicable)Not saying that you are going to make it poorly there
Post Reply