Some numbers stock hammer, cut down hammer, valve mod
Lots of numbers, maybe someone will find something useful.
12 inch TSS shooting JSB 16g chrono at 21 feet
Fill 3300
End 2200
TH .075
Stock Hammer
Valve Mod
718 PW2
876 PW8
878
873
874
858
857
856
861 PW MAX
859
854
856
851
853
850
840
834
844
841
832
830
824
824
822
814
815
810
809
804
805
804
799
794
793
34shots 1100psi
32psi per shot
Fill 3200psi
End 2100
TH.075
876 PW10
872
868
868
863
864
862
862
857
853
858
853
859
848
853
843
839
842
839
835
838
823
838
829
826
819
819
813
812
817
806
804
805
795
792
35 shots 1100psi
31psi per shot
Fill 3200psi
End 2150psi
TH .075
866PW6
868
864
868
855
858
852
855
851
841
846
842
843
839
833
831
826
822
825
817
825
816
813
814
813
810
806
805
807
805
796
793
32shots 1050psi
33psi per shot
Fill 3200
End 2100
TH.075
774 PW4
815
843
857
876
872
854
868
874
878
870
873
867
869
867
867
865
861
865
863
853
852
855
855
847
849
852
846
841
832
835
833
829
829
827
828
814
820
815
814
811
808
805
807
802
800
797
799
50shots 1100psi
22psi per shot
Fill 3200
End 2100
TH .075 –1/2turn
PW4
866
867
869
869
866
859
858
864
855
848
849
846
844
848
851
836
843
843
833
831
832
826
825
823
820
823
816
816
812
815
808
807
804
802
802
796
799
796
798
39shots 1100psi
28psi per shot
Fill 3200
End 2400
TH .075 –1 1/2 turn
PW4
719
712
697
654
703
704
699
698
699
710
708
695
711
706
710
692
695
689
703
704
698
700
692
712
676
706
680
680
676
678
692
681
692
679
677
672
682
689
665
668
682
669
666
666
683
658
663
682
657
702
663
669
674
653
654
657
654
663
626
653
657
651
654
654
658
652
644
659
687
657
646
647
660
634
642
638
639
695
643
637
639
634
633
633
634
634
632
638
646
632
635
648
636
633
639
634
635
624
624
632
628
624
103 shots 800psi
8psi per shot
Fill3200
End???
PW4
TH .075 –1 ¼
854
860
856
856
857
855
854
852
828
849
846
854
844
839
843
844
839
842
840
834
835
834
832
830
831
832
808
602
826
832
832
829
825
823
823
821
818
823
38 shots
Fill 3200
End 2200
TH 1 turn out from 0.00
Stock Hammer cut 3/16 inch shorter (shorter and lighter)
PW8
885
876
877
878
872
326
876
866
866
867
868
868
865
864
861
859
855
856
858
852
849 PW4
848
845
843
836 PW2
834
493
834
830
829
829
827
348
377
822
820 –1/8 turn TH
822
816
816
815
803 –1/8 turn (1/4 total or ¾ out)
803
803
800
802
798
802
799
799
789
790
792
Fill 3000
End 2200
Stock Hammer cut 3/16 inch shorter
TH ¾ turn out from 0.00
PW6
855
858
852
855
854
322
852
854
850
432
850
848
847
844
845
841
844
842
842
842
839
836
836
834
835
830
826
830
835
822
829
824
820
320 PW0
572
622
678
633
649
821 PW2
814
818
812
803
808
812
809
810
805
810
804
804
803
803
802 PW4
800
800
800
796
797
795
61 shots –7 low shots = 54shots 800psi
14.8 psi per shot
All Replies
I tried a delrin hammer, very inconsistent velocities. I could spend more time and probably get decent results with low tank pressures (1500-2000 fill) but it didn’t seem like I was heading the right direction, so I abandoned this route. I don’t have a scale to weigh the hammer.
I may still try other hammer options, but this is looking pretty good as it sits.
Tophat is less than .050
Valve work includes boring and (tapering entrance) of spring retainer, boring of valve stem, enlarge holes in valve stem, polish and smooth rough edges. I set the return spring (stock) with minimal preload.
I could get higher velocity, but that isn’t my only goal. I weigh consistency, curve, efficiency, and velocity in roughly that order.
Rusty
What does the hammer weigh now? Did you leave in the factory spring, you should have. Did you bore out the spring retainer? Seems a little low on velocity. Buy cutting the hammer down your affecting the springs stroke which is important. I’d think along the lines of a standard hammer length but made of delrin or ali. Get the tophat screwed down to at least .071, .070 and start from there, 15g to 20g hammer should just about do.
Thanks for all that info. A lot of work! Now I have to give it a think!
MIke
Looks good. I did a lot of experimenting with my gun, and Finally decided that I preferred the negative correlation over the curve. Especially for hunting.
Wow, thanks for the graphs.
I cut the hammer down trying to get a curve, vs. just a steady drop.
I did the valve mod and found that I couldn’t get the curve (up then down) and couldn’t get the velocity to come down.
I was shooting for velocity in the low 800s and a PW setting of 6 or lower.
I think I have found that with a curve, I will not be able to turn the velocity down on cue, which is a bummer. The closer I get to the curve I want, the farther I get from being able to manipulate the velocity on demand.
I did a bunch of shooting with a delrin hammer and found it to be ok with lower tank pressure, but very inconsistent in velocity. I could get 750fps out of 1500psi tank fills. I have a bunch more shots to input, but I am leaving out the bad strings.
I am on my 3rd tin(500ct.) of wolverines in 2 days of shooting tuning and tweaking.
The low fps shots are my getting lazy seating the breach on loading, it just pukes out a pellet if I don’t get the o-ring on the tophat.
Rusty
Damn Rusty that is A LOT of shooting!!!! Damn I would kill a skunk to have a gun shoot as consistant as yours! I’m still battling with 50+ psi jumps in some shots 😡 it’s coming along but damn…
I charted your numbers but didn’t put any comments on them in Paint…you can if you want but I LOVE looking at charts now 😆
Shots 1-149
Shots 150-290
Shots 291-441
Thanks for sharing and the good numbers too! LOVE to see how my gun is compared to others efficiency wise.
Jim.
why did you cut down the hammer?
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Yes if your after a curve your going to give up some velocity, probably around 50fps, which is acceptable. Sounds like your on the right path, good to see the tophat screwed in that far, i’ve gotten good results from that along with a lighter spring. Next was to try a lighter hammer combination, but haven’t gotten around to it yet. So many projects so little time. Good to see someone tackleing this, i know it can be done, just alot of trial and error. Keep it up, good luck.