Kiwi Airgunners Homepage
Forum Home Forum Home > Technical > Pauly's Technical Area
  New Posts New Posts RSS Feed - .25 CO2 beast
  FAQ FAQ  Forum Search   Register Register  Login Login

.25 CO2 beast
 Post Reply Post Reply
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (1) Thanks(1)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Topic: .25 CO2 beast
    Posted: 20 Apr 2026 at 6:35pm
Just want to say a big thanks to jwabfrog for sending me the .25 barrel.

I will be starting my new project over the weekend. This will be a 30PFE .25 CO2 bolt action rifle Powered by a standard Sodastream 60L bottle. This will take a while as everything will be made by me (apart form the barrel) I have been planing and researching this for the last year and i am finally ready to start.


So watch this space!
2nd place HP springer - WFTF World Championships 2014
Back to Top
-Ec View Drop Down
Senior Member
Senior Member
Avatar

Joined: 02 Sep 2025
Location: Matamau
Status: Offline
Posts: 201 		Post Options Post Options   Thanks (0) Thanks(0)   Quote -Ec Quote  Post ReplyReply Direct Link To This Post Posted: 20 Apr 2026 at 7:43pm
30FPE - that'll hit HARD.  Any guestimate on how many shots you might get from a soda stream bottle?

Going to take some careful engineering to put it together.  Looking forward to seeing this project unfold.    Good luck with it all.
Regards,
-Ec
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2026 at 7:39pm
So ive been super busy lately but i managed to get into the garage today to make a start on this project.

I have done the research but now i will test this research to make sue i am on the right track before i even start making the parts for the gun.

So i am making an adapter to screw onto the end of the Sodastream bottle. It will have a thread on both ends. One to fit the Sodastream bottle and the other to have a threaded rod that will screw into the valve of the bottle to open it. Then i will tap a thread in the side to install a pressure gauge to make sure the bottle will give me the 800PSI needed for these calculations to get the 30PFE target output.



  


I will drill and tap the rest tomorrow with a bit of luck and test.
2nd place HP springer - WFTF World Championships 2014
Back to Top
Ashman View Drop Down
Groupie
Groupie


Joined: 11 Apr 2026
Location: Christchurch
Status: Offline
Posts: 73 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Ashman Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2026 at 10:16pm
Holy sh*te there's mad ass engineers on here.
When you've finished that, any chance of building me a time machine?    Just a basic one. Nothing fancy.  Will need a dunny though.
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2026 at 10:42pm
Ha ha, sure thing!
2nd place HP springer - WFTF World Championships 2014
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 3:27pm
So just a quick update.

I have made everything and test fitted to make sure all the orings seal and so forth.

Went to the shop and swapped the empty bottle that i used as a template to cut the threads in my adapter, Screwed the new full bottle in and the threads bound up halfway screwing it on.

I have 3 bottles here as i have a sodestream machine here to make my cola for my whiskey I make. All 3 bottles have slightly different threads by the looks. one screws in just fine, the other is a little tight and the last one only gets half way.


This is going to be a problem. Their quality control on their bottles is not the best. Probably because its designed to screw onto a lose fitting plastic nut in the machine with very back low pressure.

I need my threads perfect if they are going to hold the full pressure of the CO2. So i will have a little think about who to safely overcome this problem.
2nd place HP springer - WFTF World Championships 2014
Back to Top
kruzaroad View Drop Down
Senior Member
Senior Member
Avatar

Joined: 03 Jul 2022
Location: Hastings 4 now
Status: Offline
Posts: 2965 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 8:27pm
Could you make a new adaptor that takes a sleeve you can screw in and out and have slightly differnt threads for the bottles. Can you make a adaptor for filling the bottle and get co2 in a bulk bottle and fill the canastas that work yourself?
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 9:04pm
I do not have the technology to full the bottles myself as they are liquid CO2 when full. I would need some way of freezing the gas then full the bottles in liquid state. (i think)

Making a sleeve might work but then the wall thickness of the adapter will need to be bigger to take the different inserts. this might not be practical.
2nd place HP springer - WFTF World Championships 2014
Back to Top
kruzaroad View Drop Down
Senior Member
Senior Member
Avatar

Joined: 03 Jul 2022
Location: Hastings 4 now
Status: Offline
Posts: 2965 		Post Options Post Options   Thanks (1) Thanks(1)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 9:31pm
Other option might be to get a die and just tidy up threads on the bottles that don't fit when you get them. Assuming they must be pretty close. Would still work in a soda stream when connected and wouldn't be noticed when swapping bottles
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 9:58pm
Yeah thats probably the best option. For now ill just try to find a full bottle to test that has a good thread. If it all works out ill look at what a die is worth
2nd place HP springer - WFTF World Championships 2014
Back to Top
kruzaroad View Drop Down
Senior Member
Senior Member
Avatar

Joined: 03 Jul 2022
Location: Hastings 4 now
Status: Offline
Posts: 2965 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2026 at 10:08pm
Cut one on the lathe. If your just tiding up thread basically a harden nut would do the job.


Edited by kruzaroad - 23 May 2026 at 10:09pm
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 3 hours 22 minutes ago at 5:38pm

So I solved the thread problem. I made a homemade die nut to clean up the threads.

 

I had to use another pressure gauge because the nice new one had a nipple on the bottom which got in the way of the shaft so I installed my old flat bottom gauge.

 

900 PSI is more than expected and it is winter as well with 19 degrees so that’s good pressure.





So now i can move on with the build since the tests have proven very successful.



2nd place HP springer - WFTF World Championships 2014
Back to Top
Pauly5 View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11 Mar 2013
Location: Titahi Bay
Status: Offline
Posts: 1734 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 16 minutes ago at 6:44pm
That's looking great Nunga. I can't believe I had missed the earlier posts.

I was thinking of doing a CO2 bulk fill carbine with a 30 cal barrel I have, so I will enjoy watching this.
Back to Top
kruzaroad View Drop Down
Senior Member
Senior Member
Avatar

Joined: 03 Jul 2022
Location: Hastings 4 now
Status: Offline
Posts: 2965 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 54 minutes ago at 7:14pm
What sort of pressure increase would say a 20° day give it.
Pish it to a 950psi? How consistent are you expecting the refills to be? I'm guessing that they should be pretty well pressure regulated at refill place.
Whats the next step?
Back to Top
nunga View Drop Down
Admin
Admin
Avatar

Joined: 09 Mar 2013
Location: Pukekohe
Status: Offline
Posts: 1119 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 32 minutes ago at 7:36pm
Next step is to make the 120cc tank, Hammer and ports

on a hot summers day 30.0 °C it would push it up to around 1200
2nd place HP springer - WFTF World Championships 2014
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 10.14
Copyright ©2001-2012 Web Wiz Ltd.

This page was generated in 0.032 seconds.