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.25 CO2 beast
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nunga View Drop Down
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    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!
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-Ec View Drop Down
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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.
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-Ec
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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.
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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.
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Ha ha, sure thing!
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Posts: 1117 		Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 7 hours 33 minutes ago 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.
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Posts: 2963 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 33 minutes ago 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?
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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.
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Posts: 2963 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 47 minutes ago 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
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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
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Posts: 2963 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kruzaroad Quote  Post ReplyReply Direct Link To This Post Posted: 10 minutes ago 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 - 9 minutes ago at 10:09pm
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