calculating # of shots

[Bignutsami]

In reference to here -
http://www26.brinkster.com/fullauto/index.html

If I was to use a regulator to pressurise the pressure chamber to 60psi and the "feeder tank" was presurised to 100psi, how many shots at 60psi will I get from the gun if the feeder tank has 16 times the volume of the pressure chamber?

[Bignutsami]

Think I might of worked it out.

shot-feeder pressure

1 - 100
2 - 96
3 - 93
4 - 89
5 - 85
6 - 81
7 - 78
8 - 74
9 - 70
10 - 66
11 - 63
12 - 59
13 - 55
14 - 52
15 - 48
16 - 45
17 - 43
18 - 40
19 - 37
20 - 35


My calculation for the first shot was

100 x 1/16 = 6.25
60/100 x 6.25 = 3.75
100 - 3.75 = 96 (rounded to nearest whole)

Then same done for every shot until pressure dropped below 60psi, where the second line of calculations wasnt necessary as feeder and pressure tank pressure was the same.

Does that look right?

That gives 11 shots at 60psi, which seems pretty good.