Number of Shots

[wymberley]

Short of 'suck it and see', given the necessary input information - whatever that might be - is there any way a reasonable assessment can be made of the number of shots possible from a given volume of air at a given pressure? To be perfectly honest, I'm not absolutely sure that that is exactly what I want to ask - or more precisely, how I want to word it and am hoping someone can read between the lines. We're talking PCP and I appreciate that one aspect must be the plenum chamber(?) volume.

I will not be at all surprised if for what is possibly a stupid question, PW will come up with a perfectly logical answer.

[Smudger687]

I'm sure an approximation could be derived - the work done by adiabatic expansion of gas is a cornerstone of thermodynamics so there's probably some analytical formula there. 

[eggy74]

power setting, pellet size, barrel length, regulated or not, there is alot more to it than just tank size and pressure im afraid. but do you know what gun you have in mind as there is plenty of info on the web and reviews on every size and type of gun

 

[Ultrastu]

Yeah .easy .

200 bar  down to 100 bar  70 cc of air gives with 12 inch barrel  .177  1.75 bar per shot .so 40 shots 

.22 cal 1.4 bar per shot = 50 shots 

So bigger air bottle say 200 cc 

.177  200 ÷ 1.75 = 114 shots 

.22   200 ÷ 1.4 =  142 shots 

Times this by 15 % for an 15 inch barrel 

Or 30 % for an 18 inch barrel .

Should be near enough . Guns that fill to 230 bar and are regulated  increase values by 15 %  

So a regulated. 22 with a 15 inch barrel approximately  184 shots  when filled to 230 bar .More pressure  equals more shots on a regged gun .

[oldypigeonpopper]

11 hours ago, Ultrastu said:

Yeah .easy .

200 bar  down to 100 bar  70 cc of air gives with 12 inch barrel  .177  1.75 bar per shot .so 40 shots 

.22 cal 1.4 bar per shot = 50 shots 

So bigger air bottle say 200 cc 

.177  200 ÷ 1.75 = 114 shots 

.22   200 ÷ 1.4 =  142 shots 

Times this by 15 % for an 15 inch barrel 

Or 30 % for an 18 inch barrel .

Should be near enough . Guns that fill to 230 bar and are regulated  increase values by 15 %  

So a regulated. 22 with a 15 inch barrel approximately  184 shots  when filled to 230 bar .More pressure  equals more shots on a regged gun .

Good post 👍

[Ultrastu]

Thanks .glad someone  appreciated it .

[wymberley]

13 minutes ago, Ultrastu said:

Thanks .glad someone  appreciated it .

Brilliant reply to my question. Thank you very much indeed. I’m smarting a tad if the one quoted above Is aimed at me, though. Between asking and you replying I threw a cylinder around a bit while fitting a carry strap I’d just bought. Mistake. Add this effort to carrying the R-10s about and driving to the RFD I popped both carpal tunnels. Keyboard out of the question I’m afraid. Just taken the splints off so good for a while and I’ll have a play with your figures. Once again, many thanks.

[wymberley]

15 hours ago, eggy74 said:

power setting, pellet size, barrel length, regulated or not, there is alot more to it than just tank size and pressure im afraid. but do you know what gun you have in mind as there is plenty of info on the web and reviews on every size and type of gun

 

By gum, didn't realise all that was out there and although info' on FAC kit is somewhat thin, it is there. 

Many thanks.

[Chaz25]

Um lets see, I have a 490cc bottle if I run from 3000 psi I have 0ver 150 shot but about 90 are in the prime range, this is with a 12inch barrel in .25 @ 12fpds per shot

Edited March 17, 2023 by Chaz25

[Jega]

Had my HW100 0.177 sorted by the guys at Ratworks , went from a standard 50 to 60 shots per fill to 200 to 250.

[Mice!]

3 hours ago, Jega said:

Had my HW100 0.177 sorted by the guys at Ratworks , went from a standard 50 to 60 shots per fill to 200 to 250.

Really?? Thats a ridiculous difference,  like you've put on a bigger carbon bottle. 

This isn't my kind of gun at all, but wow look at the shot count.

[Walker570]

For the majority of us I believe it is irrelevant, certainly for me. I shoot to kill (not paper) and after a couple of outings I top up the reservoir. Not run out to date although I would be pleased to do so on tree rats🤣

 

[Jega]

21 hours ago, Mice! said:

Really?? Thats a ridiculous difference,  like you've put on a bigger carbon bottle. 

This isn't my kind of gun at all, but wow look at the shot count.

Hi ,it uses a titanium cylinder the same size as a standard cylinder only 50%of the weight of a standard cylinder so way way lighter .( Sorry i quoted 200-250 per fill its actually 180-200 still mightly impressive though )

Here's their advert and spec , its not cheap by any means but for a rifle i will never sell i reckon its a good long term investment .

https://www.theratworks.co.uk/hw-100

[Mice!]

8 minutes ago, Jega said:

Hi ,it uses a titanium cylinder the same size as a standard cylinder only 50%of the weight of a standard cylinder so way way lighter .( Sorry i quoted 200-250 per fill its actually 180-200 still mightly impressive though )

Here's their advert and spec , its not cheap by any means but for a rifle i will never sell i reckon its a good long term investment .

https://www.theratworks.co.uk/hw-100

It's still like having a buddy bottle without the weight, so really good 👍