Vulcan .25 Chrono Results (2nd Chrono at 920 fps)

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Daxx

Daxx

Member
Jul 2, 2015
253
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Hello, I just tested my Vulcan with my new CE ProChrono and got the following results which I don't think are very good. Can someone help me tune it up? I'm not sure my manometer on the gun is reading correctly, but I put in what the gauge was showing each mag.

Hammer spring set to 865 FPS (54 shots)


After adjusting the hammer spring to chrono at 920 FPS (36 shots) Looks good now!


Removing the shots that were off the regulator and it looks great! 920 FPS (31 shots)
 
Ok, your chart has me at a lost for words, first you should shoot another 2 mag or until your FPS drops back down to the same or lower than the starting point 842 FPS. Second I would shoot another string I only get 3 clips shooting 34 grains, I've only done parshial strings with my 25grains because I'm almost out, when I get them I will post my string for you but my 34 grain string was 27 shots and I fell off the regulator at 125bar I started at 220 bar. Think the average was 3.33 bar per shot. ES was 26 and SD was 6. But again it with the MKII's. shoot another string for me and don't stop until you reach 6 mags or until your string falls below your first 5 shots. You regulator may be messed up.
 
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Yeah, I don't know why they set the reg at 150 bar. Mine does some of that, just not as bad. Turn the hammer pre load up till you are shooting that pellet at 900. Ultimately, I think I'll take the reg out and adjust it down to 135 bar and adjust the hammer spring from there. But I'm going to shoot a lot more pellets through it first. Turn your speed up a bit. I think your string will flatten out a bit. Velocity will still increase when it comes off the reg if it's like mine. Still a great shooting gun!
 
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militaryflipTurn up the speed to 920 fps for the first shot and do a string. If its flat then that means the regulator output is high so the speed needs to stay high.
Click to expand...
I updated the original chronograph chart above with more shots to find the drop off point. I will try turning up the hammer spring and test again tomorrow and see what happens.

EDIT: Did have time to adjust the hammer spring before I lost sun in the clouds. Got the first 3 shots at 220 BAR up to 920 FPS. Will shoot another string tomorrow and post the chart.

EDIT: Will turn down a bit to 905 FPS and start there since my max FPS in the first string was 905.
 
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reg has a tighter ES on or near the max speed it can put out but not over, lets say I adjusted the HSTA to get the max speed of 925fps then speed start to go down the more I tighten the HSTA.

so its best to set he speed to 920-925, so let say that's not the speed you want for what ever reason.

let say a well balance speed and shot count of 870-885fps --- now the reg pressure has to be lowered to max out at that speed, I think its around 130-135b

Lets talk about the brass spring guide on the .22 vulcan / daystate call it the "sling shot" same principle.

that brass spring guide is behind the hammer when fired that brass will stop by hitting the bore because the brass is larger then the bore about 1/8" before the hammer hits the valve rod. thats how it gets the sling shot affect to save on shot count / de bouncing device. 

you cant have one on the .25---it need direct impact that is needed to generate the power to open the valve wider and longer.

to minimize spring noise on the .25 I made a delrin spring guide the same OD as the hammer.

So if you want more speed on your .22 remove that brass spring guide you will gain about 20+fps more but will loose some shot count.



 
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Finished up the 2nd Chronograph after adjusting the hammer spring to get 920 FPS. Take a look at that graph now! Nice! 3rd graph is with points off the regulator removed. It looks like I can shoot 3 Mags (27 shots) and if I refill after the 3rd Mag, I should always be good to go! Thanks for everyone's help on this topic. I'm trying to learn my gun and equipment and I greatly appreciate it.

The new graphs are added to the first post.
 
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