FX dream lite bottle .25 shot count difference?? 500cc alum -vs- 480cc carbon

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starlingassn

starlingassn

Member
Feb 25, 2017
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PA (monessen), United States
really considering an fx dreamline lite bottle in .25,



but was wondering if anyone knows a rough estimate of shot count for the 2 bottles offered?



the 500cc aluminum bottle fills to 220bar (3190psi)

and the 480cc carbon fiber bottle fills to 250bar (3625psi)



obviously the carbon bottle will give more shots,

and the shot count is listed as 105 shots (im assuming this is for the carbon bottle)

but no mention of shot count for the alum bottle.



anyone have a rough estimate? if i can get 60-70 shots out of the alum bottle id be happy.


 
The reason no one replied is likely due to the number of unknown variables.

I used Lloyd's calculator and put in the 480 bottle at 3625 down to 1800psi (guessing reg setting)

I then used the 25.4 at 900ffps for 105 shots. This gives an efficiency of 1.3fpe/cuin. Now when I change the bottle to 500 and start pressure to 3190 I have to change the shot count to 83 to get the same 1.3fpe/ucin.

Now if your efficiency isn't actually 1.3, or the regulator 1800, the shot count will change. If your actual efficiency is higher then your shot count will go up, if lower it will go down with the "smaller" (less total air) bottle.

So I think (guessing at efficiency and reg setting) that you should see if the neighborhood of 80 shots (if the 480 bottle does actually get 105)
 
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I'll simplify it a little. According to my maths, the carbon bottle would give you 120000 cubic centimetres or 4.237 cubic feet. The aluminium bottle should hold 110000 cubic centimetres or 3.884 cubic feet. The aluminium bottle should be able to be shot down to slightly less volume at the same pressure as the carbon one. I would estimate that the shot count would be no more than 5-10% less. The main advantage of the carbon bottle is weight.
 
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I'll simplify it a little. According to my maths, the carbon bottle would give you 120000 cubic centimetres or 4.237 cubic feet. The aluminium bottle should hold 110000 cubic centimetres or 3.884 cubic feet. The aluminium bottle should be able to be shot down to slightly less volume at the same pressure as the carbon one. I would estimate that the shot count would be no more than 5-10% less. The main advantage of the carbon bottle is weight.
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Your #'s are showing that the CF tank has 9% more air total, which is correct. "IF" you were able to utilize ALL of the air in the tanks then you are correct with the estimate of 9% less shots (you say 5-10%), but since the gun will likely be regged in the neighborhood of 1800psi you have to take into account ONLY the available air in each tank above 1800, right? My calculations show that a 480cc tank at 3625 will have about 25% more available air then a 500cc tank at 3190, if both are regged at 1800psi.
 
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I'll simplify it a little. According to my maths, the carbon bottle would give you 120000 cubic centimetres or 4.237 cubic feet. The aluminium bottle should hold 110000 cubic centimetres or 3.884 cubic feet. The aluminium bottle should be able to be shot down to slightly less volume at the same pressure as the carbon one. I would estimate that the shot count would be no more than 5-10% less. The main advantage of the carbon bottle is weight.
Click to expand...


Your #'s are showing that the CF tank has 9% more air total, which is correct. "IF" you were able to utilize ALL of the air in the tanks then you are correct with the estimate of 9% less shots (you say 5-10%), but since the gun will likely be regged in the neighborhood of 1800psi you have to take into account ONLY the available air in each tank above 1800, right? My calculations show that a 480cc tank at 3625 will have about 25% more available air then a 500cc tank at 3190, if both are regged at 1800psi.
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Sorry if I'm missing something. By my understanding, shooting down to the regulated pressure would require roughly half of the capacity of each tank. Wouldn't that halve the difference in volume to around 4.5%? I don't think so. It certainly won't double it. If you halve the available capacity the % difference ratio should not change. 9% difference sounds more believable to me for such a small change in overall capacity. I was wrong about the Aluminium bottle to be shot down to less volume at the same pressure, as it is the opposite that is the case and ties with your calculations of available air over 1800 but I doubt that it would change the count by more than a couple of shots. By your calculations, a 9% tank size increase would yield a 25% shot count increase. I find that difficult to digest.
 
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I'll simplify it a little. According to my maths, the carbon bottle would give you 120000 cubic centimetres or 4.237 cubic feet. The aluminium bottle should hold 110000 cubic centimetres or 3.884 cubic feet. The aluminium bottle should be able to be shot down to slightly less volume at the same pressure as the carbon one. I would estimate that the shot count would be no more than 5-10% less. The main advantage of the carbon bottle is weight.
Click to expand...


Your #'s are showing that the CF tank has 9% more air total, which is correct. "IF" you were able to utilize ALL of the air in the tanks then you are correct with the estimate of 9% less shots (you say 5-10%), but since the gun will likely be regged in the neighborhood of 1800psi you have to take into account ONLY the available air in each tank above 1800, right? My calculations show that a 480cc tank at 3625 will have about 25% more available air then a 500cc tank at 3190, if both are regged at 1800psi.
Click to expand...

Sorry if I'm missing something. By my understanding, shooting down to the regulated pressure would require roughly half of the capacity of each tank. Wouldn't that halve the difference in volume to around 4.5%? I don't think so. It certainly won't double it. If you halve the available capacity the % difference ratio should not change. 9% difference sounds more believable to me for such a small change in overall capacity. I was wrong about the Aluminium bottle to be shot down to less volume at the same pressure, as it is the opposite that is the case and ties with your calculations of available air over 1800 but I doubt that it would change the count by more than a couple of shots. By your calculations, a 9% tank size increase would yield a 25% shot count increase. I find that difficult to digest.
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No, it would double it. And the 9% difference could change by a lot more then that depending on how high the reg is set.

OK lets do it this way. We agree that the CF at 3625 has 9% more then the Alum at 3190.

Let's say the alum tank has 1000 molecules which means the CF has 1090

Now lets say the molecules to make to get to the reg set point (non usable) are blue, and those above the reg (usable) are red

If it take 500 blue (1/2) to get to the reg pressure then the alum has 500 red and the cf has 590 red, 500 compared to 590 is an 18% difference .

If it takes 800 blue to get to the reg pressure then the alum has 200 red and the CF has 290 red, 200 compared to 290 is a 45% difference.
 
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Sorry, you lost me at molecules. I was just trying to make it understandable without unnecessary gobbledegook. The only true way of knowing is to try it.
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Sorry, you lost me at molecules. I was just trying to make it understandable without unnecessary gobbledegook. The only true way of knowing is to try it.
Click to expand...

OK do you agree that any air below the regulator is not unusable? Since shooting below the reg would change the velocity?

By your calculations the 480 tank has 4.237cf (at 3625) and the 500 tank has 3.884 (at 3190) so this is a difference of 9% - (4.237/3.884 - 3.884/3.884)

Now the 480 tank should have a capacity of 2.1cf at 1800psi and the 500 tank has 2.199 at 1800psi. This is the unusable air.

If we take the unusable air away we have the following 480=2.137 and the 500=1.692cf. This usable air difference is 25.9% (2.137/1.692 - 1.692/1.692)

If we go to 2000psi then the capacity of each is 480=2.338 and the 500=2.435.

If we subtract this 2000psi of unusable air we get usable capacities of 480=1.899cf and the 500=1.449 which is a difference of 31% (1.899/1.449 - 1.449/1.449)

Now run the reg all the way up to 3180psi. The 500 bottle now has .014cf but the 480 has .52 which is 37 times the amount of air.

Using these equations you should be able to see that as the reg pressure goes up so does the additions percentage of usable air with the higher pressure vessel.
 
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Guys I have both 500cc alu and 480cc CF they both air up to 250BAR. The OP is getting a Dreamline which airs to 230 BAR so I'm thinking the 500 wins.
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Nope, the Dreamline bottle gun with 500cc is 220bar and with 480cf is 250 bar. See specs below (You may be thinking of the Dreamline Lite with cylinder not bottle)

and with any reg setting above 1800psi you will see a 20-25% difference in shots (which will go up as reg pressure goes up) using the 480cf tank.

FX Dream-Lite Bottle with Donny FL Moderator

  • Smooth sidelever cocking action
  • Synthetic, quick-release skeleton stock
  • Smooth Twist X barrel
  • Barrel length: 500mm/19.685” (.177 & .22), 600mm/23.62” (.25 & .30)
  • Overall length: 37.75” (.177 & .22), 42.25” (.25 & .30)
  • Aluminum version Weight: 6.65 lbs. (.177 & .22), 6.95 lbs. (.25 & .30)
  • Carbon Fiber version Weight: 5.9 lbs (.177 & .22). 6.25 lbs. (.25 & .30)
  • Repeater
  • Magazine Capacity: 21 (.177), 18 (.22), 16 (.25), 14 (.30)
  • Air cylinder: 500cc Aluminum bottle or 480cc Carbon Fiber bottle 
  • Carbon Fiber Fill pressure: 250 BAR (3,625 psi)
  • Aluminum Cylinder Fill Pressure: 220 BAR (3,190 psi)
  • Foster quick-disconnect fill fitting
  • Shots per fill: 190 (.177), 135 (.22), 105 (.25), 42 (.30)
  • Muzzle energy: 18 fpe (.177), 32 fpe (.22), 47 fpe (.25), 75 fpe (.30)
  • Fully Shrouded barrel with Fixed DonnyFL Moderator
  • AMP (Adjustable Match Precision) regulator
  • Externally adjustable hammer spring tension
  • 2-stage adjustable match trigger
  • Hogue AR-style pistol grip
  • 11mm dovetail rail for mounting optics
  • Forend Picatinny rail for bipod/accessories
  • 3-step transfer port adjustment
  • Includes magazine and 3-year transferable warranty


 
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lol heres what bob said.



While the two tanks may contain about the same amount of air, you don't use ALL the air in the tank, only that above the setpoint pressure of the regulator.... If the reg. is set at 2000 psi, you have 1625 psi usable in the 29.3 CI CF tank, but only 1190 psi in the 30.5 CI aluminum one.... That works out to 3280 std. CI of air for the CF tank but only 2503 std. CI of air in the Aluminum one.... So, feeding a gun regulated at 2000 psi, the CF tank should get about 30% more 
 
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What also is to consider is the air course. If you do not own a compressor, would you go and refill your scuba tank when it is as high as 220 bar? If not, the 500cc tank would gain a litle more volume and shots below that. If you have a 300 bar tank, it might not be that many refills before you drop below 250. To really benefit from the 250 bar pressure, you had to refill your tank quiet often. 
 
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