HomeBuilt Airgun — Done!

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    Finally finished my homebuilt project.
    17 inch .357 barrel. 22 cubic inch tank.
    This will be the first of 3 or 4 guns. I have 4 more barrels, two .25 cal, one .22, and one .223.
    Now I gotta learn Anodizing.
    Not quite Buba B’s quality! He’s a tough act to follow!



    That is a fine piece of work. With that valve of yours I bet it is a real cannon. Maybe Duracoat would be an option?

    Whats it look like over the chrony?


    Looks bad over the crony!
    The same valve kicks out 30 gr Kodiaks @ 1050 FPS in .25 Cal.
    On this gun the velocity = 700 FPS with a 65 gr round ball. Thats about 70 FPE.
    700 FPS is barely usable!
    Tried Hitting it with a 400 gram steel hammer and the present 175 gram aluminum Hammer. I got a big spring in there, much stronger than a stock SS.
    I know the valve is opening fully, because it stuck full open twice, and dumped the tank (fixed that problem a while back).
    Expected at least 120 FPE from this gun.
    The barrel is short, only 17 inches????
    Tried boring out the valve orface, got no change in velocity. My standard orface is .170 inch, this gun is up to .200 inch.
    I got all winter to work out the valve problems, but I’am out of ideas.
    I need help! Cygnus, what am I doing wrong?



    Looks good, Cygnusx should be able to help you out with the valve.


    Thats a funny 2 weeks lol , good to see its done, im about to go through all the fustrations of valve tunning myself ,so i wish you luck 😀 .
    What happened to the two triggers ? and i see the checkering has been put on hold too ! This just a time thing lol 😀


    Buba b:

    I had a sear like airforce’s but found it to be unreliable. (maybe it was that elongated hole thing??), So I redesigned the trigger mechanism and abandoned the double trigger. Yep, no checkering, I built this grip just to get me by till I get checkering tools. The darn performance issues slowed me down for a week.
    Buba your work sets the standard around here!!
    I’ll be very interested in your home anodizing — Thats something I need to do also.



    Mark here is your reward….

    I hope you like it…. 😆


    The upper part (sear?) drops away cleanly to let the hammer fall.



    Grats MM looking forward to seeing the tuning of your new gun!

    400 Gram hammer 😯 wholly crap!

    If I remember correctly I was getting 950 fps with 60 grain Eun Jins, a stock Condor valve 120’sh gram hammer, 17″ 9mm barrel, 3,000 PSI fill. I was getting very near your numbers with a stock talon valve.

    I never was able to get a shroud to work worth a crud on the .308 or 9mm be cool to see if you can work something out that takes the BARK out of the 9mm.

    Cygnus ought to be able to get your valve working in the scary range!

    Really looking forward to seeing how you sort your gun out.



    Thanks for the info! Now that I know it can be done , I’ll try harder.
    My numbers are crapy. I’m getting 765 Fps — about 85 FPE.
    Blows through a 2 by 4 with no problem, But there should be a lot more power available.
    I love the feel of this gun! The barrel is cut thin, and the the 22 cubic inch tank is light weight. The home designed/built trigger worked out really well. The trigger pull does not change much with increased spring pressure, and it cocks smoothly!
    I built a new valve this afternoon (from scratch), but no improvement in velocity. Dam!
    The hole through my breach is .5 inch diameter. Do you remember what yours was??



    Mark, sure have enjoyed your build posts. Sure can learn allot from what you have done and then posted.


    Roy S.


    Beautiful job Marc,

    I like the trigger config.

    Something to be proud of…..


    sorry didnt see this post until now….catch me on msn pm me for details i hate spilling my email adress publicly

    lets chat

    400 gram is crazy…there should be no need for it, 100-150 is all you should need, especially with stronger spring in there.

    heck im running 150 gram in my 457 pushing 600 fpe, something is up with your valve….but chat me and ill do my best to help you out


    Nice man, I love the simple trigger mech. What resets the trigger after firing? Is there a return spring of some sort thats not in the drawing? You could still add a safety to that set up easily if you desired.


    Mark, I have a question.

    What length did you make the frame tube overall?


    Roy S.

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