Discovery Chrono numbers

[Pete]

I have 22 Cal. discovery. I installed a HDD, and a power adjuster. With a 2000# Psi fill. shooting 14.3 grain Benjamin pellets. I shot 22 rounds through a chrony and the best was 735 going dwn to the 600 after 22 rounds.  The PSI gauge went dwn to about 1500 PSI. I tried adjusting the power adjuster but 735 was the best I coud get. Is this normal ?
                   Thanks Pete

[preez]

Pete, it should shoot faster than that, mine in .22 shoots 780-790fps @ 2000psi  and I don't consider it fast, some Disco's shoot over 850fps. It might be the HDD slowing it down, it might be too much lube around the hammer too. Try removing the HDD and see what happens.

Hope this helps

Chris

[onelight]

Pete I think I lost about 50 fps with the HDD I posted some of the numbers from mine a thread or to down.
  I put in the HDD and power adjuster at the same time so I am not sure what fps loss is due to the HDD
but I think others have posted a slight loss with the HDD with an increase in shot count.
my velocity seems to be highest between 1500 and 1000 psi on the gun guage, but I have not run enough shots over the chrony at different fills to know what is best yet.
  Many of the guys here can give you much better info.than I can.   Mark

[ziton]

Dumb question. What's a HDD?
Don

[Truman]

I think it's to stop the hammer bouncing on the valve! It's a little plastic tube like thing that sits behind the hammer!

[Pete]

I took out the HDD and left the power adjuster in from a 2000 PSI fill to 500 PSI  I shot 44 rounds thru chronoy
44 578
43 609
42 620
41 634
40 655
39 662
38 676
37 686
36 701
35 707
34 717
33 728
32 737
31 740
30 744
29 751
28 757
27 763
26 761
25 760
24 768
23 772
22 769
21 772
20 770
19 776
18 766
17 770
16 764
15 762
14 752
13 764
12 752
11 758
10 758
9 745
8 744
7 744
6 746
5 746
4 738
3 737
2 731
1 710
I then took the power adjuster out and put in the stock spring , 2000psi fill dwn to 500 psi again

41 565
40 583
39 606
38 625
37 638
36 652
35 664
34 686
33 694
32 703
31 714
30 730
29 743
28 753
27 756
26 763
25 777
24 783
22 790
21 805
20 799
19 806
18 799
17 816
16 809
15 814
14 811
13 817
12 807
11 816
10 819
9 807
8 816
7 815
6 810
5 809
4 801
3 801
2 798
1 797
  I think I will just leave it stock and no modifications I just use it for plinking and pest control .

[melloroadman]

Were did you get the P.A. Marvin

[Truman]

I've got a new disco in .22. Comparing it with my Gamo Maxima .22 which shoots at about 720fps, the disco unmodded is alot faster, maybe in the 800-850fps! I don't have a chrony so I used chairgun to work backwards. It would be nice to know the real figures but I'd need to sweet talk the missis again and I don't think my luck would stretch to a chrony just now! Yours sounds a tad slow but I could be wrong with the figures for my two!

[Pete]

Marvin
    I ordered it from Big Ed some time ago , had some family problems , and just got around to putting HDD, and PA in.
 I have been reading your posts about redrilling the lower link,  Iam thinking about trying it.  Do you still recommend this mod?    
                  Pete

[melloroadman]

When I taken to him my e -mail it sounded like he had several different springs . I know he uses a different guide than most but you might ask if he has a stronger spring . Or go to the local hard ware store . The trigger mod worked good for me . But I have a career 201 S that has a heavy trigger pull so I put my trigger back to stock except for the small spring and have gotten use to heavier pulls this way . My groups are just as good now as before. I am glade I did it since I shoot the discovery so much now when I shoot the career it is not a problem . I have learned to control my trigger squeeze , It is not a jerk or pull any longer .Marvin