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View Full Version : 1385+ shots = 68/4500


DRAGON
11-23-2006, 05:49 PM
I played paintball last weekend and had my tank filled to 4500psi at a local shop prior. I ended up only using my LP Imagine for the games I played, which were few. This is a renegade field and my buds that are normally there with hpa in a scuba tank weren't so for once I didn't add any pressure to the tank at all. I didn't really check the tank pressure when I got to the field. As some of us know, when you get a tank filled, the end result of pressure is usually a bit lower after the tank cools down. I have had the tank end up just above 4000psi after getting it filled to 4500psi before after cooling down. I did check the pressure before I left the pro shop and it was 4500psi dead nuts -

In the few games I did play in I just so happened to shoot 1000 balls exactly. I just checked my Crossy and it still has 1250psi left in it. So the way I figure it, I'm getting at least 1385+ shots from this 68/4500psi tank.

4500
1250
-----
3250psi(or less) used for 1000 balls

3250psi divided by 1000 balls = 3.25psi per ball

1250psi divided by 3.25psi pr/bl = 385 balls(rounded)

1000 balls + 385 balls = 1385 balls per 4500psi(technically)

**did I figure that right mathematical geniuses?**

All this did not include dry fires and what-nots in between and possible less starting pressure but should be fairly accurate though prolly a little more. Not bad I suppose for a regular LP'd Spyder. I've heard some ridiculous numbers like 2100 shots from a 68/4500 on the net before. I think people that post things as such are pathetic for attention, have some erroneous math skills or both -

I'm a bit curious about the shot count on the new VS's since they have the lighter striker and from what I have gotten, in reality run relatively 250psi. My Imagine runs at 300psi @ 280fps. Anybody actually have any valid numbers on the VS's perhaps? Anybody have any valid numbers for their LP Spyder's in general? -

'05 Imagine
Palmer's Stabilizer
Rocket valve(completely opened)
Blocked striker exhaust port
Modified stock VA
Modified stock bolt
Modified striker
Modified stock BL ASA
Light 32* main spring
14" J&J ceramic barrel
Ultra Evil paint

Chris Cole
11-27-2006, 08:16 AM
Not bad, I used to get 1200 out of my 68/3k on my E-99. I almost miss that gun.

Moe
11-27-2006, 10:05 AM
sexy

Spinal
11-27-2006, 06:54 PM
any pics of this blocked striker exhaust port?

calebh
11-27-2006, 07:36 PM
no you didnt do the math right, but i dont think there would be a very large diff. the more paintballs you shoot, the more pressure per ball you use, to keep the operating pressure in the marker the same. theres also the point at which the pressure in the tank reaches the operating pressure and the marker can't shoot anymore at a decent fps.

its still pretty good efficiency for a spyder, however you slice it

DRAGON
11-27-2006, 08:11 PM
no you didnt do the math right, but i dont think there would be a very large diff. the more paintballs you shoot, the more pressure per ball you use, to keep the operating pressure in the marker the same. theres also the point at which the pressure in the tank reaches the operating pressure and the marker can't shoot anymore at a decent fps.

its still pretty good efficiency for a spyder, however you slice it

.........1000 balls + 385 balls = 1385 balls per 4500psi(technically)........

That's why I put the 'technically' disclaimer in there. If I had a tank full of pressure and 3/4 of a case of paint to waste, I could do it to the exact number. I'm not willing to throw that much paint down the toilet. I did not count dry fires and other side technicalities in the numbers including the loss of pressure after the tank cooled off after the fill. That alone could add 100's of psi -

Technically I could prolly get better as well. I normally top the tank off between games. The math as far as the mathematical formula is correct and that's what I was posting about. Not what could be upheald in a court of law lol -

druid
11-28-2006, 04:26 AM
Once I get a new tank reg for the GoodYear, I'll be making a shots/tank post...that ought to be interesting to say the least...lmfao

ShadowX
11-28-2006, 08:30 AM
I had a similar expierence. I shot one pod (140) shots.. and about 60 dryfires, maybe more.. And I used 500 psi off of my PMI 68/45 (when i started it was at 4000 and was at 3500 when i was finished)

Correct me if i'm wrong, but that is 200 shots on 500 psi, which equals about 1400-1600 shots on a 4000 psi filled 68/45..

Keep in mind this was a STOCK spyder xtra.. I was using PMI premium and it had a pretty good fit to the barrel...

I think i may have done a math error somewhere, but IDK... Weird..

calebh
11-28-2006, 03:51 PM
ya, again, it takes more more psi to shoot a ball the less pressure you have in your tank. its not taking more air, the operating pressure in the marker is the same, but the psi in the tank will drop faster as there is less pressure available to replace the pressure in the marker. also, on a stock spyder, you probly wont get any decent shots below 750 psi or so.

its the same math as is used to calculate how many fills you'll get out of a scuba tank, just on a much smaller scale. if anyone is willing and able to pull it off, go ahead. its a nice mix of chemistry and calculus. i havent taken calculus, and if i can avoid it, never will.

timmyshoota
11-28-2006, 03:57 PM
You gotta remember, at a certain point it will stop shooting. You can't go all the way down to 0psi. Somewhere around 500psi it'll stop recocking, maybe a little lower. That should still get 1300 shots though.

Hob Hayward
11-28-2006, 04:13 PM
And you didn't factor in that dryfires use more gas a real shot.

calebh
11-28-2006, 06:41 PM
on the stock spyder, i doubt it. its not a linear equation, and 500 psi isnt enough, for me anyway, to estimate. if this was a linear equation, sure, 1300 sounds reasonable. but no.

on drago's, the fact that he had shot most of his tank already means that he can get a much better estimate on his remaining shots with linear reasoning (if thats the right way to say it). 1385 is unlikely, but possible.

hob's right, too. but i dont think they would make much of a difference unless you're talking 200 or 300 dry fires. not real sure about that.

Spinal
11-29-2006, 08:52 AM
pics of striker exhaust port blocker thingy?

bigred76
11-29-2006, 11:57 AM
Hob's not entirely right... The valve will let out however much you allow it to, so if you chronograph it to shoot, say, 275fps, then it will use EXACTLY the same amount of air to fire real balls and dryfires as well. 1385 is decent, but I still got better from my LP Spyder... heh... 700-750 (depending on leaks and such) from a 48/3k. :D By math, that would mean.... 1487.5 shots from a 68/45? Lord knows how many Druid was getting from the Esprit, either. I'm just waiting for him to post up his numbers.

EDIT: Forgot to say I parted out the marker long ago (about a year and a half ago, now), and can't remember all I had on it. So no specs, unfortunately. If I find the thread I posted them in, I'll post them up.

DRAGON
11-29-2006, 06:05 PM
any pics of this blocked striker exhaust port?

Wasn't going to take it apart specifically to get a pic for you but I was tinkering tonight and took a pic for ya -

http://www.imagestation.com/picture/sraid220/p46a89419ac120cfc7d2f8796e121d542/ebd5386d.jpg

Just tap it to 6-32(no need to drill because the hole is relative for the 6-32 tap), clear the burrs w/a pin file on the inside(lower tube) and using your fingers, just use a slightly larger drill bit on the outside to lightly chamfer the hole, then blue Loctite a 6-32 X 1/16" set screw in the freshly tapped hole making sure it's not protruding past the inside surface of the bottom tube. Using any other valve outside of the Rocket valve and all it'll do is cause recocking probs -

Spinal
11-30-2006, 06:44 PM
wait so, if i don't have a rocket valve, that mod is basically useless? how about with a tornado?

calebh
11-30-2006, 07:10 PM
Hob's not entirely right... The valve will let out however much you allow it to, so if you chronograph it to shoot, say, 275fps, then it will use EXACTLY the same amount of air to fire real balls and dryfires as well.
you sure? theres no backpressure from the ball to keep air from escaping on its own, and on a blowback at least, that pressure helps close the valve and recock the marker. when i was tuning my lp spyder, there was one point when it would not recock without a ball in there, suggesting that more air IS used when dryfiring... maybe with an electropneumatic the air used is the same, but im very doubtful about blowbacks...

timmyshoota
11-30-2006, 08:39 PM
you sure? theres no backpressure from the ball to keep air from escaping on its own, and on a blowback at least, that pressure helps close the valve and recock the marker. when i was tuning my lp spyder, there was one point when it would not recock without a ball in there, suggesting that more air IS used when dryfiring... maybe with an electropneumatic the air used is the same, but im very doubtful about blowbacks...
More air isn't being used, there's just no backpressure. The valve is still open the same amount of time as with the ball, so the same amount of air is being used.

calebh
11-30-2006, 08:59 PM
then explain my marker not recocking when theres not a ball in it, but working fine with one... im afraid im gonna go with the logical conclusions from my own experiences on this one. given that, even if you post some super technical study someone performed proving that the amount of air is the same, i might still go with my own experience.

bigred76
12-01-2006, 04:43 PM
Your valve is still open the same time, but it routes the air out the barrel more because of no backpressure (as you pointed out) when there is no ball. If there's a ball in the breech, then the air is encouraged to go out the back of the valve slightly more as that's the only other place it can go (if the ball's snug in your barrel). It don't make much sense... but that's what happens.

calebh
12-01-2006, 08:48 PM
i see what you're saying. i have few difficulties understanding mechanics of things. my thing is, if the air is encouraged to go the way of the striker, since there is a ball in the breech, the valve would be open a very slightly shorter time, because the air pushes the striker back faster. if it doesn't recock, the striker was not pushed back with as much force, and would keep the valve pin depressed slightly longer... which, if the pressure is great enough, would force it back to be recocked, and still use more air. but since there's no ball, it keeps venting out the barrel, instead of forcing the striker back.

i think my theory is even more complicated than yours lol

timmyshoota
12-01-2006, 08:58 PM
You kinda got it. The backpressure air doesn't really make the striker reset quicker, just aids it in reseting. Without the aid, it doesn't have the force to push all the way back.

calebh
12-01-2006, 10:02 PM
exactly. which leaves the valve open slightly longer, right? not a lot, but enough to make a difference over a few hundred dry fires.

bigred76
12-01-2006, 10:13 PM
Nope. The valve opens, and closes, at the same amount when you have it shooting with or without balls at the same velocity. You have to remember that the valve pin is slotted, and allows air out the back whether or not it's open.

DRAGON
12-01-2006, 10:31 PM
Maybe I can clear this up. When there is no ball in the breech and a shot is taken, it uses more propellant because there is nothing stopping the pressure including the LPC storage from depleating as much as it can for the duration of the dwell time. W/A ball in the barrel, the ball is actually buffering/blocking the maximum flow of pressure for that quick ms and by the time the ball leaves the barrel the valve is closed. Less pressure has been used because the valve is closed before the ball that's blocking the maximum flow of pressure has left the barrel -

Far as the striker goes, the same thing applies. The ball is blocking the freed up escape of pressure so it has to go somewhere and in this instance the path of flow to the striker is another escape route for the pressure. With no ball in the barrel there is a large gaping path for the pressure through the barrel. When involving gasses or liquids under pressure, the largest escape orifice is where the majority of gas or fluids will escape -

timmyshoota
12-01-2006, 10:39 PM
So we were right up except for the part about the ball barricading and not allowing more air, which inturn uses less air.

We were trying. :(

bigred76
12-01-2006, 10:41 PM
I still disagree, but eh, I can't prove myself.

I have to clear this up though, Drago: are you an engineer?

DRAGON
12-01-2006, 10:45 PM
I think you were correct but maybe didn't think about the cup seal blocking the pressure as well as the ball - ;)

.......... Drago: are you an engineer?

Nope, they only let me ride in the caboose because I drive too fast lol - :D

bigred76
12-01-2006, 10:52 PM
Hmm, thought just occured to me. The ball's blockage would be affected by none other than the barrel's bore. The fit around the ball would determine how much air required to push it out the barrel, and thus how much air is used. So I might just be right... I'd have to test it, though. But... I'm not willing to do that short of a paycheck, haha!


I think you were correct but maybe didn't think about the cup seal blocking the pressure as well as the ball - ;)
And 'tis must be late at night if you're getting things backwards again.... lol.... So, if you don't drive the train, then you must be a machinist? I'ma keep guessing until I figure it out because it keeps bugging the hell out of me!

DRAGON
12-01-2006, 11:09 PM
The barrel to paint( I said that bass ackwards didn't I?) fit would only determine how much excess might be used past the point of a loose fittin ball as opposed to a tight fitting ball. That has to do with efficiency and porting comes into the equation as well. Even a loose fitting ball blocks off a maximum current of flow because it is indeed an obstruction just the same -

bigred76
12-01-2006, 11:18 PM
I see what you're saying, now. I forfeit (Only time you're gonna hear that one from me....). It's just too much math for a simpleton like me to do, and I don't have the equipment to do it will. Hell, I don't even know what I'd use to test it, lol!

calebh
12-01-2006, 11:24 PM
so i was right that dryfires take more air. yay.

so just for my own info, is the valve open any longer when a blowback is fired without a ball in the breech?

bigred76
12-01-2006, 11:33 PM
No, you're not right, Drago is. :dodgy:

Read Drago's post more carefully, I'm too tired at this hour to restate it. ;)

DRAGON
12-01-2006, 11:40 PM
I would guess the dwell duration is the same whether there is a ball in the barrel or not. It is controlled by springs not pressure. It's really no secret that you can depleat a tank full of pressure much more expeditiously with no paint -

calebh
12-01-2006, 11:50 PM
more air IS used when dryfiring

When there is no ball in the breech and a shot is taken, it uses more propellant because there is nothing stopping the pressure including the LPC storage from depleating as much as it can for the duration of the dwell time. W/A ball in the barrel, the ball is actually buffering/blocking the maximum flow of pressure for that quick ms and by the time the ball leaves the barrel the valve is closed. Less pressure has been used because the valve is closed before the ball that's blocking the maximum flow of pressure has left the barrel

so i was right that dryfires take more air. yay. (emphasis added)

so go :dodgy: yourself. after you read more carefully.

my valve theory may be wrong. i dont think so. but it may be.

bigred76
12-01-2006, 11:59 PM
I was kidding... Yeesh... :rolleyes:

This is basically the answer to your theory:
I would guess the dwell duration is the same whether there is a ball in the barrel or not. It is controlled by springs not pressure.

calebh
12-02-2006, 12:16 AM
I would guess the dwell duration is the same whether there is a ball in the barrel or not. It is controlled by springs not pressure. (emphasis added)

its controlled by springs, but the pressures involved seem to play a role. unless someone wants to set something up and measure the diff, i dont think this discussion's goin any further. good luck lol

bigred76
12-02-2006, 12:49 AM
Yes, the pressure on the cupseal helps it stay closed. That would be common sense, agreed? Now, let's say the marker runs at 300psi. You can raise the pressure through the vertical regulator to stiffen the valve spring, and lower it to soften. Odd, eh? Well, it's because of that pressure on the cupseal holding the valve closed. The more pressure holding it closed, either by an air mass or a spring, and it will have a lower dwell. Softer, and it will have a higher dwell, because the valve is knocked open more or less. This is actually how you tune springs for an Autococker, but I find it transferable to Spyders as well.

Just a minor explanation of how valve dwell works on blowbacks. ;)

And... Drago's "guesses" are almost sure enough to bet on. Stick around long enough and you'll learn that. :)

calebh
12-02-2006, 01:15 AM
Stick around long enough and you'll learn that. :)

haha, ive been around a long time ;) i took a long break and missed the changeover on the forums, and im just now starting to become active again, but i have been around lol. a guess is still just a guess.

im not meaning operating pressure when i say the pressures involved. i know how all that works. again, ive been around a long time ;) im meaning mainly the pressure created by a ball in the breech, or lack of one, affecting everything else. since i havent been disproven yet, im still going with my own experience and the conclusions i draw from that.

DRAGON
12-02-2006, 10:57 AM
I emphasized the word guess because it would really depend on what pressure and what springs pertained. Did I mention components & flow properties? There are so many variables that one could only guess what significance pressure would have on dwell. I will stick my neck out and say pressure would have no significant affect on dwell duration in a stbb. The springs are obviously the main determiners of that -

In an EP marker the dwell duration is controlled by the board commanding a duration of flow through the noid. The dwell will always be the same(set to a particular ms increment in thousandth's of a second) whether the pressure has been changed or whether there is a ball in the barrel or not. The only thing that pressure dictates is the amount of flow that goes through the marker. A stbb isn't very much different besides the fact that it uses springs which makes a world of difference in price as opposed to that expensive $100 noid and added chipped program to the board -