Tuning WILDCAT MK1 shot string

[tsmith]

i have a cheap caldwell chronograph. seems to work ok. but i get a few intermittent low readings about 20 fps slower. i am waiting at least 5 or more seconds between shots. i started the fill at 230 bar and shot til my speed started to drop. hammerspring is at about 96% of full power. the speed seems to slightly increase in the middle and end of the string. HUMA reg at 135 bar shooting 33.95 jsb in .25.

anyone ever see these random low speed shots in a string like this?

shots 16, 36, 5

Created: 05/18/21 05:25 PM

Description: wildcat string 5/18/21

Notes 1:

Notes 2:

Distance to Chrono(FT): 1.00

Ballistic Coefficient: 0.046

Bullet Weight(gr): 33.95

Temp: N/A °F

BP: N/A inHg

Altitude: 0.00

# FPS FT-LBS PF

72 783 46.23 26.58

71 791 47.17 26.85

70 783 46.23 26.58

69 794 47.53 26.96

68 804 48.74 27.30

67 799 48.13 27.13

66 807 49.10 27.40

65 809 49.35 27.47

64 806 48.98 27.36

63 807 49.10 27.40

62 810 49.47 27.50

61 804 48.74 27.30

60 810 49.47 27.50

59 804 48.74 27.30

58 806 48.98 27.36

57 804 48.74 27.30

56 802 48.50 27.23

55 798 48.01 27.09

54 800 48.25 27.16

53 800 48.25 27.16

52 798 48.01 27.09

51 797 47.89 27.06

50 804 48.74 27.30

49 794 47.53 26.96

48 801 48.37 27.19

47 804 48.74 27.30

46 805 48.86 27.33

45 805 48.86 27.33

44 800 48.25 27.16

43 798 48.01 27.09

42 801 48.37 27.19

41 798 48.01 27.09

40 786 46.58 26.68

39 794 47.53 26.96

38 796 47.77 27.02

37 798 48.01 27.09

36 776 45.40 26.35

35 789 46.94 26.79

34 801 48.37 27.19

33 799 48.13 27.13

32 800 48.25 27.16

31 797 47.89 27.06

30 794 47.53 26.96

29 802 48.50 27.23

28 794 47.53 26.96

27 797 47.89 27.06

26 796 47.77 27.02

25 798 48.01 27.09

24 788 46.82 26.75

23 799 48.13 27.13

22 796 47.77 27.02

21 804 48.74 27.30

20 806 48.98 27.36

19 796 47.77 27.02

18 806 48.98 27.36

17 799 48.13 27.13

16 772 44.94 26.21

15 797 47.89 27.06

14 797 47.89 27.06

13 786 46.58 26.68

12 790 47.06 26.82

11 789 46.94 26.79

10 792 47.29 26.89

9 795 47.65 26.99

8 809 49.35 27.47

7 804 48.74 27.30

6 795 47.65 26.99

5 773 45.05 26.24

4 796 47.77 27.02

3 793 47.41 26.92

2 798 48.01 27.09

1 784 46.34 26.62

Average: 797.3 FPS

SD: 8.1 FPS

Min: 772 FPS

Max: 810 FPS

Spread: 38 FPS

Shot/sec: 0.1

True MV: 799 FPS

Group Size (in): 0.00

 

[Guest]

Try setting it up with higher reg pressure and less hammer spring tension...set reg up to 160 bar and start shooting over your chronograph with hammer spring nut turned in about 5 turns in but no more than 8 turns in...too much hammer spring tension is your problem so to get the velocity you seek set the reg higher instead of maxing out your hammer spring tension. My Wildcat MKI has an extreme spread of 3 ft/s & standard deviation of .86 ft/s....mine won't get as many shots as yours but I go for quality over quantity every time...at 50 yards my Wildcat will put 5 shots into the same hole clean - she just stacks each shot on top of the one before it over and over...and that's with JSB 33.95gr Heavy at 900 ft/s for 61 ft lbs of energy. Try it you might like it...

All the best, Chuck

 

[tsmith]

Try setting it up with higher reg pressure and less hammer spring tension...set reg up to 160 bar and start shooting over your chronograph with hammer spring nut turned in about 5 turns in but no more than 8 turns in...too much hammer spring tension is your problem so to get the velocity you seek set the reg higher instead of maxing out your hammer spring tension. My Wildcat MKI has an extreme spread of 3 ft/s & standard deviation of .86 ft/s....mine won't get as many shots as yours but I go for quality over quantity every time...at 50 yards my Wildcat will put 5 shots into the same hole clean - she just stacks each shot on top of the one before it over and over...and that's with JSB 33.95gr Heavy at 900 ft/s for 61 ft lbs of energy. Try it you might like it...

All the best, Chuck

i will maybe give it a try. but i like shot count. maybe i will try 150 bar. still may get 50 shots. 800 fps with 34 gr jsb is plenty to kill what i hunt. Thanks. I’ll let you know if i change the tune.