Vulcan velocity problems.
Hello this is my first post here. I have a gen II Vulcan that has been great until about a week ago. I shot the gun and it was really quite like it wasn’t powerful so i got the chrony out and it was shooting somewhere around 700 fps from 250bar. the velocity started getting back to normal around 200bar it would get up to around 900 fps. So i took the gun completely apart and replaced the high and low pressure o-rings in the regulator. put the gun back together and filled it up. It was shooting at about 530fps then climbed to 630 fps. I increased the hammer tension and got the gun shooting 830 fps, by this time i was at about 200bar. then the gun spiked up to 920 fps at 180bar then started dropping at 140. I filled the gun back up and the same 530fps so i’m wondering why its shooting at 530fps on a full fill.
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Viewing 9 replies - 1 through 9 (of 9 total)
your hammer spring is all intact in good shape as if it was new or?
That sounds like a good idea I will probably do that before adjusting anything on the reg.
Yes I took my hammer spring out and everything looks good.
Do know where to find an adapter like that or have a link?
with a mark2 you can measure the regulator just need to replace the venting grubscrew with an adaptor for a pressure gauge. make sure your gauge can take the full cylinder pressure if the regulator pressure runs away.
your hammer spring is all intact in good shape as if it was new or?
Okay I just went out and chronyed it after adjusting the valve a full turn and in still getting the same results. I’m going to go ahead and adjust the rregulatr like you said kris and see if that works.
if it is a .25 then it should really max out at 140 and not at 180. i think your reg is stuck open. so the seat and seal dont meet. ernest has some cricket adjustment video watch that, yours is not closing.
well when you are in you can inspect your return spring too, the valve returns spring. maybe it is Z shaped too so the valve cant open fully anymore.
you need to answer the question of what is your reg is set to.
dont rely on the gauge on the gun, only if it is the new style, original can be off, mine was showing +40-50bar.
normally i would say, for sub12fpe .177 you set the reg to 70bar, 90for full power .177, 120bar for .22 and up to 140bar for .25.
you fill your cylinder ONLY to this pressure, you need a gauge you can trust or you need a reference to compare to do this and with this setting you setup the hammer spring.
then you fill the cylinder to 200bar and so and double check power output.
look i would not fill the gun too high, the reg does not like it, also the o rings suffer, 220max.
maybe someone can measure the hammer spring length of their guns to tell you what they got, i have a .177 so different model.
maybe your gauge is off by 40bar, and thats it.
I got the new hammer spring a few months back it was the same length as the original. My gun is a .25 cal. I’ve compared the gauge on my tank to the cylinder and they seem to match up. When the gun was working it would always fall off the reg at 140bar according to the cylinder gauge I never mest with the settings on the reg. I’ve been adjusting the valve like zonk said so I’m going to have to shoot it over the chrony again and see if there is any difference.
you may have a too short hammerspring. or the regulator is set way too high or letting through all cylinder pressure. or combination of both .
you need to answer the question of what is your reg is set to.
dont rely on the gauge on the gun, only if it is the new style, original can be off, mine was showing +40-50bar.
normally i would say, for sub12fpe .177 you set the reg to 70bar, 90for full power .177, sub12 .22 50-60bar, full power .22 120bar and up to 140bar for .25 full power.
you fill your cylinder ONLY to this pressure, you need a gauge you can trust or you need a reference to compare to do this and with this setting you setup the hammer spring.
then you fill the cylinder to 200bar and so and double check power output.
look i would not fill the gun too high, the reg does not like it, also the o rings suffer, 220max.
maybe someone can measure the hammer spring length of their guns to tell you what they got, i have a .177 so different model.
maybe your gauge is off by 40bar, and thats it.
by the sound of it your gun behaves like an unregulated gun, is there any plateau at all so the reg works or it is just letting the full cylinder pressure through? have you got a chrony so you can get us a full string?
Mine did the same thing when it was new. I sent it to Ernest and he found the problem, it was the valve. He adjusted the valve and it’s been shooting + or – 3fps for over several thousand rounds now.
I think the regulator is not regulating the pressure. How did you set the regulator pressure?
Viewing 9 replies - 1 through 9 (of 9 total)
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If you took the regulator apart to replace the o-rings then just putting it back together won’t bring the regulator back to 140bars. I think the regulator is not regulating at all and the gun is shooting directly off the airtube. For a 25 cal it should be set at 140bars.