FX Impact X Velocity Variations

[Kwreece]

Hello,

First time poster and avid PCP airgun fan. I recently purchased an FX Imapct in .30 caliber. It is tuned to 145 Bar. Love the gun and the accuracy. In doing testing on high power I am getting velocity spreads of just under 20 FPS. Is this normal. Below is a typical shot string after the gun has been topped off.

Created: 10/21/18 05:24 PM
Description: Imapct
Notes 1: High Power Test
Notes 2: 
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 44.75
Temp: 54 °F
BP: 27.69 inHg
Altitude: 2200.00
# FPS FT-LBS PF
22 900 80.50 40.28
21 902 80.86 40.36
20 903 81.04 40.41
19 903 81.04 40.41
18 905 81.40 40.50
17 900 80.50 40.28
16 908 81.94 40.63
15 901 80.68 40.32
14 906 81.58 40.54
13 906 81.58 40.54
12 911 82.48 40.77
11 912 82.66 40.81
10 909 82.12 40.68
9 909 82.12 40.68
8 910 82.30 40.72
7 908 81.94 40.63
6 912 82.66 40.81
5 911 82.48 40.77
4 914 83.02 40.90
3 913 82.84 40.86
2 914 83.02 40.90
1 917 83.57 41.04
Average: 907.9 FPS
SD: 4.9 FPS
Min: 900 FPS
Max: 917 FPS
Spread: 17 FPS
Shot/sec: 0.1
True MV: 908 FPS
Group Size (in): 0.00

Going lower with the power using the power adjustment wheel yields even bigger stained deviation numbers. Any feedback or suggestions on tightening this up are much appreciated.

Ken





Ken Reece

516 424-0372

 

[milacik]

interesting, i thought the other way around is the norm here. lol

probably a flow issue.

 

[Glem.Chally]

Im no expert but isnt that shooting hot for 145 bar?

 

[STO]

There are a lot of possible causes for this, but given that your shot spread seems to be trending down my first guess would be that your reg hasn't quite finished filling between shots. Some of this may also just be because your gun is new and the reg is still breaking in. If someone hadn't told me that was a thing when my Crown was new, I'd have been tearing my hair out over it. A couple hundred rounds later and it is dead steady. *shrug* 

 

[edosan]

If the gun is new is ok until de regulator start operating normal (new regs need time to settle) 

 

[Kwreece]

Thanks everyone. I have put a little over a 1000 rounds through it. One of the comments makes me wonder if I am not waiting enough time between shots. The velocity seems to drop as the shot string increases. I will continue to test as I eye that Huma regulator

 

[heavy-impact]

Does your regulator creep up about 20 bar overnight? Mine does and I have a Huma high pressure 145-190 on the way.

 

[FukoChan]

The ES is normal. Utah airguns (i saw it on their custom rifles) has a crown with a ES of 26. I believe under 20-30 is fine. Try sorting your pellets by weight and see if it improves. My old impact had a ES of 23 and it was very very accurate. Getting below 10 is rare and below 20 is great!!!

 

[John "spysir" Blount]

20 fps ES is the Maximum you would want to live with in airguns. Ninja regulator have no issue holding a 10fpe ES.

Your numbers seem right.



John

 

[milacik]

that is a trend, it should NOT be there, some spread up and down from shot to shot YES, you would expect that but not going lower and lower or higher or higher.



what you need to do is to lower the initial speed then you will have more shots with closer velocities. i have no impact so sorry cant tell you exactly what to adjust but it needs a bit of tuning.

 

[Kwreece]

Thanks everyone for the comments. After another 500 rounds it seems to have settled down. I do notice the first few shots after a new fill will sometimes be hot, but it settles down after that. This is a string from yesterday.

Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 0.00
Temp: 17 °C
BP: 29.95 inHg
Altitude: 0.00
# FPS FT-LBS PF
24 910 0.00 0.00
23 908 0.00 0.00
22 910 0.00 0.00
21 910 0.00 0.00
20 909 0.00 0.00
19 911 0.00 0.00
18 912 0.00 0.00
17 912 0.00 0.00
16 910 0.00 0.00
15 911 0.00 0.00
14 913 0.00 0.00
13 911 0.00 0.00
12 911 0.00 0.00
11 910 0.00 0.00
10 911 0.00 0.00
9 911 0.00 0.00
8 908 0.00 0.00
7 913 0.00 0.00
6 912 0.00 0.00
5 912 0.00 0.00
4 911 0.00 0.00
3 915 0.00 0.00
2 910 0.00 0.00
1 912 0.00 0.00
Average: 911.0 FPS
SD: 1.6 FPS
Min: 908 FPS
Max: 915 FPS
Spread: 7 FPS
Shot/sec: 0.1
True MV: 911 FPS

 

[Drumsnguns]

My Impact .25 shoots around an ES of 11 on average. I've had as good as 8 and as high as 15. I have the original regulator and my ES improved when I took it apart and polished everything incl. washers with 3M polishing paper.