Building a Modern Pneumatic Airgun

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Jonny:
Yes typo that pound sign, duly altered.
Serious dosh not for use down the cut, scope was near £1200 6 years ago but can pay £3k now with mounts.

First air rifles made cost me around £20 for the wood, £20 butt pad, £6 hydraulic tube, £5 springs and screws, free barrel and approx £15 of ancilliary items.

Stot:
I have an idea for an adjustable 2 stage trigger but not sure on it at the moment I need to do some testing to see if it will work as I hope.

Your current gun reminds me of the Alros Trailsman TDR. Trigger on that was very... agricultural and is what gave me the idea for the trigger i'm planning as I wanted to replace the trigger on it.

--- Quote ---Did a semi bullpup in 95 in stainless G316 S11, trigger block 13" long no linkages and long first stage returning. Could hold in vice blow on blade and it would go off.
--- End quote ---

That sounds similar to what I have in mind only twice as long, but I'll leave the details until I'm there though, just incase It fails miserably and I change it completely. :D

Cheers
Stot

cfellows:
Just found this thread and have read through it with interest. I have both of Buckley's books, but in the end, I built a bulk CO2 air rifle based more on the Stealth layout. I like your poppet valve approach better than Buckley's. What's the diameter of the delrin valve head? Also, what size thread did you use on the valve stem?

Thx...
Chuck

Here's a link to my CO2 air rifle...

http://www.youtube.com/watch?v=1n-EXv5lLbE

Stot:

--- Quote from: cfellows on November 19, 2010, 11:16:11 AM ---I like your poppet valve approach better than Buckley's. What's the diameter of the delrin valve head? Also, what size thread did you use on the valve stem?

--- End quote ---

Hi Chuck,

I seen your video before actually when I was first looking at building something its a great setup. :clap: Great thing about the book design is it should run nicely on CO2 with just a little adjustment, especially with a 24" barrel. :thumbup:

The book doesn't cover the poppet valve head too well in the schematics. Theres no sizes or anything for making the seal and cap. Also looking at the recess in the pin that aids airflow in the schematics, it looks like its in the wrong place, i.e. the edge of the recess is in line with the transfer port with the pin is at rest, rather than when the valve is open. So I decided to do it my way.

The poppet valve head is 9mm-6.5mm @ 60 degrees. I threaded the valve pin M4 and left a shoulder on it then self tapped it into a 3mm hole in the delrin. I had to re-design the valve pin to accommodate the tapered seat but it seals real nice.

Haven't done anything on it this week, Got to get the hammer tube done over the weekend and im coing to case harden the valve pins too. :coffee:

Cheers
Stot

Stot:
Well a few days since my last update but I'm at a stage where parts of the design for one part is dependant on the design and position of another part.

As standard the book rifle has seperate hammer cocking handle and bolt handle. I want the rifles to be bolt cocking only so I have had to redesign the breech block, the bolt, the hammer and the hammer tube slightly. Also roughed up the trigger assembley so now I have positions of all the areas I have to mill on the hammer tube and breech.

I threaded the hammer tube to take fit the valve the same way I did the air tubes and what this all means is the last parts I have to turn are the bolt and handle, the hammer and the hammer tube end cap. The rest is milling operations so Ill get the turning out of the way then set the lathe
up for milling and do the lot.

First up was the hammers.

* Threaded the hammer tubes to fit on the valves.
* Faced off and turned down some stock to slip fit the hammer tube.
* Center drilled then drilled through the stock.
* Bored out a recess for the hammer spring to guide in.
* Turned the stock around and turned the other end down under size. This is because the shoulder that is left will be the sear.
* Polished it up, hammer done.

Ill case harden these too so the sears work nicely. :thumbup:

Cheers
Stot

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