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SPVMBR

Posted: Wed May 28, 2008 9:01 am
by bigbob12345
Well here is a little gun I threw together lately.
The name stands for Silenced Piston Valved Marble Rifle(SPVMBR)
Here is the gun

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I gave it a satin black paint job(that turned out rather nicely) and I made a silencer for it.
The silencer is not very affective at all, but it does quiet it down somewhat. I realize that an effective silencer needs to have lots of volume, but if I made a larger one it would have ruined the looks.

And I wouldnt go as far as calling this thing a sniper as it doesnt have a scope and you cant shoulder fire it(stupid ball valve).

So here are the specs

Chamber:24in of 1in sch40 pvc piping
Barrel: About 40in of 1/2in sdr21 pvc pipe(I havent measured so Im just guessing)
Piston valve:1in tee with 1/2in porting
Pilot:1/2in ball valve
Piston1in wooden dowel with neophrene sealing face bolted on
Silencer1in sdr21 body

Well so about the power.
The power is very good for a gun so small(as shown in the videos)
And it is loud for its size(as said before, the silencer is not that effective)

I know it is very similar to my ISM but I wanted something better looking, and a little more manageable.

So pic and vid time
First some vids, then some pics.

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entry
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Exit
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The ball valve pilot
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The fill valve
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The barrel support
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the silencer
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Posted: Wed May 28, 2008 9:12 am
by MaxuS the 2nd
Wow, you've got really dirty hands. Gloves?

Good amount of power. :D
You seem to be a machine at pumping out launchers recently.

Posted: Wed May 28, 2008 9:21 am
by bigbob12345
The dirty hands is just spray paint, and yes I should of worn gloves.

And yes I have been building a lot lately, now that I have found an extremely cheap source of parts.

Posted: Wed May 28, 2008 9:31 am
by starman
Good work there BB! Compact design and very effective. I'm sure it's easy and quick to pump up to pressure. Also, the black paint job looks great!

Tip for the day: A little gasoline will take that paint off your hands, then wash it off immediately with soap and water.

Posted: Wed May 28, 2008 10:09 am
by JDP12
SEcond tip- use mineral spirits instead of gasoline.... i dont want to waste gas money on that with the way prices are going :roll:

Posted: Wed May 28, 2008 10:37 am
by sniper hero
very nice gun :D
I like the paint job
try some shots from a big distance

but is it ergonomic?

Posted: Wed May 28, 2008 10:49 am
by starman
ilovetoblowthingsup wrote:SEcond tip- use mineral spirits instead of gasoline.... i dont want to waste gas money on that with the way prices are going :roll:
Well, the last time I looked, mineral spirits still costs more per gallon than gasoline....about 4X. And, we're only talking about a little splash in the hands, not enough to take a bath in.

He's more likely to have some lawn mower gas handy.

Posted: Wed May 28, 2008 12:01 pm
by THUNDERLORD
Impressive for such a small chamber :shock: It's probably nice to be able to pump it up quickly and still have plenty of power.

Hope you're careful of riccochets at such close distance. 8)

BTW that water bottle/spray can moved hellafastly(new word) :D
EDIT:BTW2: As far as gas prices cleaning your hands thing, guy in video owns 2 oil tankers I heardhttp://www.youtube.com/watch?v=nYNt-MlA ... re=related :?

Posted: Wed May 28, 2008 5:41 pm
by bigbob12345
Starman: Gasoline idea is good, although I already got it off using a couple minites of hard scrubbing.
And yes it is very quick to pump up, takes about 5 seconds to get it to 100psi

ilovetoblowthingsup: Well I have loads of gas laying around but no mineral spirits, so Ill just go with the gas.
And starman is right, the gas is cheaper.

Sniper hero: I would do long distance shots if I had a exhaust for the piston valve that allowed me to shoulder fire it.
Right now with the ball valve there is no chance I will hit.

Posted: Wed May 28, 2008 11:17 pm
by OuchProgramme
Hmm...silencer doesn't seem so effective?


Nice kick to it though

Posted: Thu May 29, 2008 4:58 am
by Dumb-kid
oo very nice cannon

should use some trigger pilot and a nice that will look great

btw you killed the can haha :lol:

Posted: Thu May 29, 2008 8:18 am
by bigbob12345
ouchprogramme, as stated above the silencer hardly makes any difference in the sound, but it does make a tiny difference and it just looks cool :wink:

Dumb kid:I really do need some sort of pilot I can shoulder fire with. Maybe Ill just go buy a sprinkler valve this weekend.

Posted: Thu May 29, 2008 8:23 am
by Dumb-kid
for a quick piloting sprinkler valve are good

well yeah silencers for spud cannon are pretty useless but it look good

Posted: Thu May 29, 2008 8:29 am
by bigbob12345
Well in the cas of piloting, a 1in ball valve is more effective than a 1in sprinkler, this is because there is enough time for you to open the ball valve all the way before it fires and a ball valve lets more flow through than a sprinkler.

And I have had silencers be very effective before, especially on combustion cannons. The silencer just need to have a lot of volume, and this one has next to none.

Posted: Thu May 29, 2008 8:40 am
by Xerxys
Hey what d'ya know you have the exact same pump as I did. I broke it on bottle rockets after realising it was shite ( but that was probably after i broke now that I think about it...)

P.s. nice paint job, it looks like one of my piston cannons