Q:

Interesting discovery on .25 vulcan.

I found this to be interesting. Me and a friend bought our .25 vulcans at the same time. In our chrony test his was shooting jsb heavys at 850’s. We thought the chrony was misreading. After 3 different chrony test he ran a string on his caldwell which has a cool phone feature. Here is his number with jsb king 25gr.
08-18-2015 08:03:51 PM
08-18-2015 08:03:51 PM
Description:
Notes 1:
Notes 2:
Distance to Chrono (FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight (gr): 25.400
Temp: 77 °F
BP: 29.89 inHG
Shots
# FPS\FT-LBS PF
18 931\49\24
17 936\49\24
16 938\50\24
15 942\50\24
14 948\51\24
13 950\51\24
12 952\51\24
11 949\51\24
10 946\50\24
9 950\51\24
8 951\51\24
7 946\50\24
6 949\51\24
5 948\51\24
4 948\51\24
3 952\51\24
2 955\51\24
1 942\50\24
Average: 946.28
StdDev: 6.23
Min: 931
Max: 955
Spread: 24
True MV: 946.39
Shots/sec: 0.37
Group Size (IN): 0.00
Reg need to be adjusted! ! 3200psi 2 mags?? Only good for 14 shots!!

Airgun Technology

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Viewing 8 replies - 1 through 8 (of 8 total)

quote keyser soze:

I just shot my .25 through the Chrony. The Volcano is shooting 930 for 40 shots with an ES of 4.3 fps and SD of 1.67. Falls off regulator at 110ish

Impressive. Mine looks like it would do the same.

Sent from my Z30 using Tapatalk

I just shot my .25 through the Chrony. The Volcano is shooting 930 for 40 shots with an ES of 4.3 fps and SD of 1.67. Falls off regulator at 110ish

We agree that the reg is set a little high. It drops off at 150bar. I played with mine a little and got shooting sweet at 9 teens to 920.

quote Airgunwhore:

My Vulcan did the same thing when I got it was shooting around 900 fps using jsb 25.39 grain then about after 500 pellets I chrony it and my fps had increased to 925 -940 so I just put another 500 pellets thru it then chrony it again the spread tightened up I’m now 2000 pellets thru it and last time I checked my extreme spread was 6 over 36 shots and the reg settled in at 920 -925 (4mags) so I would get more rounds thru it let everything settle in lil more before tinkering

Wow, that’s a lot of pellets for the gun to settle on a “final” pellet speed. I have seen 500 before but not 2000. When I get my (.22) Vulcan I’ll me sure not to chrony it too soon and expect my scope settings to stay exactly the same.

I have not put mine over the chrony since I got it. Will have to do that once and put up same data from compare

Sent from my Z30 using Tapatalk

My Vulcan did the same thing when I got it was shooting around 900 fps using jsb 25.39 grain then about after 500 pellets I chrony it and my fps had increased to 925 -940 so I just put another 500 pellets thru it then chrony it again the spread tightened up I’m now 2000 pellets thru it and last time I checked my extreme spread was 6 over 36 shots and the reg settled in at 920 -925 (4mags) so I would get more rounds thru it let everything settle in lil more before tinkering

Here is a 2 mag string of my Vulcan .25 shooting KINGS…..I started at 250 BAR and was reading around 200 BAR after second mag. Going to run a full regulator string soon. FPS was tightening towards the second mag. Not an expert by any means, but I’m thinking my regulator is working correctly. I’m running compressed Nitrogen and have about 500 shots run thru the gun so far. My Chrony from Tony showed around 917 FPS when new. I’m guessing the nitrogen and the regulator wearing in upped the FPS.

That doesn’t sound right..

Viewing 8 replies - 1 through 8 (of 8 total)

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