Vulcan losing air when cocked
Hello – Newer guy here and have upgraded from a few AF guns to this Vulcan a few months ago. Love the gun and the feathered vermin are nervous to say the least. I do not usually cock the gun until I am about to shoot it but today on two occasions I did cock it and had 15 or 20 minutes wait till i shot it – two darn lucky crows they were !! Needless to say I hit extremely low ?? I got home and shot it across the chronograph and got 918 fps. I cocked it, let it sit for 10 min then got 630 fps !?!? I’m bleeding down for some reason ?? Anyone have any suggestions. I bought it new about 2 months ago maybe, actually Superbowl Sunday..
Thanks for any help..
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Thanks Keyser – I will try to do the shot string this week or next weekend. I do not notice a drain on the gun if it sits for a few days just what i described before after cocking the gun and not shooting it for awhile.
Thanks for the help
After complaining Evengy got rid of the bleed screw. If you have a new gun it is not there. I was going to put an annotation on my video but everyone turns annotations off on YouTube anyway.
So on to your problem. This is not a leak. The hammer is not consistently opening your valve or you have a bad Oring in the regulator.
Could you please post a shot string with a bar reading every 10-20 bar. This will help me Dx your problem.
Keyser – I did the balloon check and not filling of the balloon.
graham82 – I watched the video and do not seem to have a bleed screw that I can find and any suggestions on how you would check the other area?
too high pressure in the prechamber => low power, does it make sense?
if you suspect the reg, just fill it to its regulator setting, and see if the problem remains, keep refilling shoot it a lot with constant off reg but low pressure.
maybe your reg is stuck open and whatever is in the cylinder reaches the knock open valve, then this can but may not open every time.
try to fill it to lower pressure, you did not say what calibre so cant tell the number.
Ok the way the system works is the valve screws onto the end of the air tube. Cocking the gun should be independent of the valve. If you valve is leaking it can be diagnosed by using a ballon on the end of the barrel. So what I would do is fill the gun to 250 BAR. Remove the moderator. Place a ballon on the end of the barrel. If the ballon doesn’t fill then cock the gun and repeat the test. Let us know the result.
I’m wondering if your problem was like mine. Mine would shoot 913 fps for a dozen or so shots then it would drop down to 600fps and then back up to 913 fps again. I believe Ernest said the problem was the valve. Does it shoot low EVERYTIME you cock it and let it set, or every once in awhile?
Check out this review (14:00 min)…he says two most likely places for leaks are manometer & bleed screw.
https://youtu.be/CMla8nm2iRE
Edit: Just reread your post…so it only leaks when it’s cocked?
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Your problem is most likely due to high pressure building in your plenum due to a leaky O ring in the reg.. replace the orings its an easy place to start.