Re: PBM update

[Frank Pittelli <frank-at-rctankcombat.com>]

William and Melissa Johns wrote:
> At 07:01 AM 7/17/2004, Will Montgomery wrote:
> 
>> We are not regulating the CO2 pressure.  The CO2 tank pressure is 
>> around 800 psi.
> 
> Good lord.  I liked John's 275 psi a lot better.  Where the hell am I 
> going to find a solenoid valve that can handle 800 psi?
> 

Bill, as one data point, when I built my o-ring based PBM, I was using 
150psi to fire the paintballs, which broke every single paintball.  Of 
course, o-ring guns use pressure to fire the paintball, not volume, so 
I'm not sure if that helps you at all.  I've got a spare regulator that 
I can loan you if you want to try it out with a CO2 bottle (standard CGA 
fitting), as well as some different springs that change the output 
pressure of the regulator.  I think there are some for 120psi and some 
for 180psi, but I'll have to check on that.

I know that homemade PBMs based on "dump valves" (aka sprinkler valve 
guns or spud guns) only use about 100psi which is the rating for those 
valves.  And, I heard an interview with one of the top-notch pumpkin gun 
guys who said that they beyond a certain pressure (I think it was 
120psi, but don't hold me to that) it doesn't change the muzzle velocity 
of the gun because the diameter of the valve is the limiting factor. 
So, I suspect that you'll need something in the 100-150psi range, but 
that's just a guess.

 > At 03:02 AM 7/17/2004, Boris "need a real muzzle" Harpman wrote:
 >
 >> May I ask what is the accurate range of the paint you are shooting ?
 >

Every tank has good accuracy within 25 meters and some tanks have good 
accuracy beyond that point, depending on the barrel type and pressure 
setting on the marker.  When test firing the 155mm artillery piece in my 
backyard, my daughter was consistently hitting the center of a tree that 
was about 30 meters away.  By my rough estimate, most "hits" are scored 
within 25 meters which seems to be the preferred battling distance, but 
we repeatedly see sporadic hits from further out.

So, if your marker is consistently hitting the target at 60 meters, 
you've done very well.  Congratulations.  Of course, accuracy has a way 
of changing on the battlefield when others are shooting at you!!!

        Frank "Keep Em Flying Straight" Pittelli