Gun threads cut and valve results.
Well, The die came today and I managed to cut the threads, It went very easily. Cut like a dream.
One thing I did notice, Looking at the cutters on the die, Using it one way around which had more of a rake angle. It cut okay but seemed to CHIP away the metal rather than cut it. The other way around with less of a rake angle it cut well, Seems like the brass didnt like the high rake angle.
Im trying it in stainless steel in a few days, give me strength 😀
So, now onto my ultra flow valve results. With a large valve opening and 4 ports in the stem, at 2000psi (What I want to get my reg set at) I was only getting 650 fps with 27 grain pellets. I let the pressure drop to about 1800 psi and got 760 fps, I then let it drop to 1400 fps and got 860 fps.
I now need to increase the hammer spring tension so that the valve will open fully at 2000 psi and the should hopefully get me up to around 1000 fps with the 27 grainers so I should settle around 950 with 31 grain barracudas
Dave
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Looks great 😀
Just went out to shoot the above pellets.
I moved my chrony into better light.
Shot a 42 grain at 835.7 fps = 65 FPE
a JSB King at 25.4 (I thinkg) went 999.3 fps = 56 FPE
Tried a 38 grain eunjin and it wouldnt even fit in the barrel. I didnt try any others but it was a really tight fit, I didnt feel like ramming it in the barrel so I took it out and called it a day.
Without any silencer it if FKIN loud and I dont think the neighbours would appriciate loads of shots.
Im going to make a 1/2″ UNF adapter (Or buy one if im too lazy) for my barrel and buy a SAK moderator. I have one on a .17 HMR and it works really well.
Dave
Thanks pab, Was a bit of luck really but it is doing exactly what I want at the moment.
Im going to go out again and shoot a JSB king, 38 grainer and 42 grainer again.
Dave
Going to go out and test it now, wish me luck 😀
Barrel shortening is fine, From what length to what length?
Dave
24″ to 20″ plus new ali’ bushings would be ideal…(I’ve got delrin bushings at the mo’ and would much prefer ali’ ones)
Bang on!! 😎
Perfect speed for the Barracudas, Eunjins must of been just too big, otherwise you should of seen faster fps than that.
Shoot the JSB Kings already! Reckon you’re right, about 1000 odd fps…
Double post but it is because it is relevant.
Just chronied the gun, With a 1/8″ connector in the back of the regulator pre-chamber, (So I know if the volume is sufficient) Pumped it up to 2000psi.
Took a shot with the 27 grain H&N rampoints, 976 fps. Totally blew through my 2×4 backstop but I did have a 10mm steel plate behiend that. Amazing power.
I then wanted to test penetration, so I pumped it back up to 2000psi (It had fell to about 1400 psi) I then shot down the top of a 2×4 (Compressing the grain) and had 75mm of penetration :D:D I was loving this at that moment.
So I grabbed a 31 grain Barracuda, Stuck it in the spout, pumped it back up to 2000psi, Put up two 2×4’s as a stronger backstop, and shot……………. wait for it…….. 950.0 fps :D:D Thats was exactly what I was looking for. I then looked at the backstop (A much larger hole compared to the .22’s) and then saw a nice splatter of lead on the steel plate. The pellet had made it through both 2×4’s
Just for fun, I grabbed a 42 grain sam yang/enjuin (sp?) which was a tight fit in the breech and it shot 776 fps.
So lets review
27 grain at 976 fps = 57 FPE
31 grain at 950 fps = 62 FPE
42 grain at 776 fps = 56 FPE
The 42 grainer might have been a chrony error because I was shooting under some branches but it could have also been that it was too tight in the breech or the regulator chamber just isnt big enough to get the heavier pellet going, or 2000psi just isnt enough energy to get the power from the 42 grainer.
Should put the Laser accurate JSB’s right at 1000fps 😀
Attached photos are how it will look when its finished. (And my S410)
Im a happy chappy 😀
Dave
Cheers, Ive just changed from 65mm hammer+spacers to 75mm to see if I can get it opening at 2000psi
Going to go out and test it now, wish me luck 😀
Barrel shortening is fine, From what length to what length?
Dave
Damn Dave, thats looking really good! 😎
And the shroud looks awesome!
May be on your case soon for some work (barrel shortening)!!
Here you go Pabs (And the rest of you)
Pretty simple really, pictures should explain themselves.
One little think I did do, was thread the front of the stem so it will accept am M6 grubscrew. I will buy a few and drill diffrent sized holes in them for diffrent power settings, I wont have to worry about power curves etc. Because its reglated.
The grubscrew installed in the stem has no hole in it because I need to buy a small set if drill bits.
Oh and the last four are of a shroud I made for an 18″ .25 before and after paint
Enjoy
Im painting my regualtor pre-chamber at the monent and will get pics up when its dry and installed
Dave
Okay Okay, I will see what I can get you
Dave
Piccys??
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Again, about perfect for the JSBs 😎
Good job Dave 😎