.308 Build
Ordered all the pieces from AF today so I can build my .308 Condor. Frame, trigger asembly, power wheel, fore arm grip. I have 28″ barrel and bigbore Blod valve. I will make everything else. Lathe is going to be here around 12:00 tomorrow. Can’t wait to start making things on a real lathe. I will then have .22 .25 and .308. Want to try and break 400 fpe with .308.
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IMHO
Dump is coming from .430″, go to .375″ dia..
No hammer spring pressure when breach is against valve.
Assuming your valve spring is sized correctly.
So if I settle for 250 fpe I should have a accurate gun? I guess I’m almost there. Maybe a tophat setting of .095″ will get me there. Thanks for onfo.
That is right in line with the CORSAIR.
Getting over 300 FPE is VERY HARD from a 308. 400 FPE is well, almost impossible. Beaumont and Dan have gotten 300+ with about a 4000-4200 psi fill. The problem though is accuracy with the 1-20 and the 1-16 twist barrels. I’ve had 2 buddies with 2 different platforms get into the 900-960 FPS with HPA and accuracy was horrible. One had the LW 1/16 and the other had a Haley 308 with a 1-20 twist. You FPE/FPS now is right on par with my cosair and my other buddies guns for ultimate accuracy
I think on air I will be happy with 300 fpe. 400 fpe is with helium of course. I’m getting around 270 fpe with helium in .25 with 3000 psi right know and 167 fpe on air. 5000 psi of helium is crazy. I still have some work to do before I can start testing again to see if I have solved tank dump issues.
150 gr. 827 fps 227 fpe
126 gr. 886 fps 220 fre
118 gr. 944 fps 233 fpe
Wow, not been here for sometime and what do I read, I want one.
When you get a ME of 400 FPE with a .308, not burning powder, I want to be first in line. I’ll pay the price just to see how you accomplished that feat.
I am not the best in the world at making air guns, but I’ve tried. With everything I have tried, the best so far was 330 FPE with a 150 Gr. round nosed @ 5,000 psi helium, 28″ barrel with shallow groooooooooves, lapped barrel and no lube.
I gave up and am satisfied at about 240 and a 150 gr. Very accurate out to 300 yards.
Got it working with tophat at .080″
150 gr. 827 fps 227 fpe
126 gr. 886 fps 220 fre
118 gr. 944 fps 233 fpe
Have a few issues and no time right now so it will be a couple weeks before I get it going again.
I had tank dumps when my spring was on high tension with 95g hammer, and that screw regulating the valve closing spring was not screwed in good. Maby its somthing simmilar to high hammer spring tension + too weak valve closing spring ?
Finished the valve today and got to fire it. I have one slight problm, tank dump. What would cause tank dump on a bigbore? It did manage to go 825 fps with 150 gr on 3000 psi. The only thing that I can figure is I have no o ring on the stem until tomorrow. I tried stiffer return spring with no luck. Here what it looked like when I fired it. Had a #2 spring clamp holding the trigger spring plate in.
Might make it side cocker. Finished the hammer and breech today. Going to use a pretty big spring, the one in the pic it is .0785″. Im running .072″ right now in my .25. Put it all together to cycle it and it’s not to bad to push and cock. No trigger yet so all I could do was push it and bring it back. Was also making sure breech worked.
I turned a piece of aluminum to the same as the barrel so I can test fit without the barrel. Yes I will make a nice knob for it. I use the stock knob when I machine the notch. I screw it in, then set it in the vice with the knob on the bottom. It sets on the knob and then I tighten the vice.
out of curiousity…. side cocker? dang boy… that’s one helluva project!
Machined barrel today. Breech is .430″ and machined the barrel where the hammer rides to .600″. Made 2 brass breeches, one for me and one for back40rob’s .308. Will make one out of aluminum. Going to lighten it up once i threaded it for knob. Will put together a frame tomorrow and make a hammer for it. Then I have to figure out how big I’m going to make the valve stem. I think I’m going to go with a .375″ with a .312″ hole. Lot’s of things to do and 2 days before I go back to work.
Doug was that done with the condor valve or with another one. I know you were gonna try it with the condor valve.
Yes lathe did come to day and Gearhead(Joe) came over and helped me get it setup. A little disapointed. My $800.00 collet chuck did not make it and they forgot my drill chuck. Last time i talked to them i was told I had to put oil in it but didn’t say I had to supply it let alone how much I need to get. I would have picked it up when I bought all my insert tools. I got internal and external threaders, a 12″ boring bar, left hand cutter and a cut off tool. All carbite inserts tools.
Helium. Kinda on the expensive side to get 3000 psi of helium. Here in CA it is hard to get 6000 psi of helium. They won’t sell you the tank and they want $2.50 a day to rent a tank. Only one place fills the 6000 psi tanks. So I went for the booster set up. $575.00 for booster and reg from Roachcreek used. Another $300.00 for CGA 580 helium setup and some fittings from Joe. $42.00 for 80 cf 2300 psi tank(let me use the tank). So that’s what it took me to get 3000 psi of helium. I did it just to see what it would do. I had been looking into it for a while.
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Yeah I went and picked up a selection of stiff valve springs. I also have changed to 3.5″ hammer spring to keep the pressure of the tophat. Have you seen my valve how the spring is center mounted?