GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Redrum4fun on September 14, 2017, 03:19:33 PM
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So I like many have been after the ability to shoot the JSB 18.13 through this rifle in a manner that doesnt resemble 12GA splatter so I tookl the rifle apart to remove the spacer between the Spring an Hammer to see if I get any nearer to 800FPS. Otherwise this rifle just loves the H&N Baracuda Match .22 Cal, 21.14 Grains, Round Nose, 5.53 mm. To bad they only come in 200ct amounts at about 5 cents a shot :P
In the process of putting her back together I notice there is a lot of slop in OD/ID of the pictured parts. My question is Does this matter in the slightest? Im pretty certain I could use Teflon tape to remove this gap without fear of it getting into my transfer port. Obviously I don't want to add anything that I don't have to so I posted up here. Thanks for any input on the picture.
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I would say that gap isn't important as long as you have a seal between the tank valve and that part. Best way to increase or decrease the velocity is to adjust the hammer spring
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Thanks yes.. but the spring has limited adjustability on the AT44-10. Other threads talk about this method and jbwelding valve ports.. which may be the next step.
Thanks
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Well it's time to put her back together and see what if any FPS reduction I get without the spacer between the hammer and spring. Might as well see about trying to remove that gap. Cant hurt as long as I keep it clean and free of the port.
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HOLY SMOKES !!! Removed the spacer between the spring and hammer on the rifle. Went to shoot through the chrony and ..lol.. 400FPS
Just came back inside to measure the spacer so I can go get some washers to stack. I find it hard to believe that nobody has mentioned this type of result that I have seen anywhere.
900 FPS down to 390-400 FPS... I dont know what to say.
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That's a big change. Good job.
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Not what I had expected. So I went out to the homedepot and bought some stainless #6x32 nuts that measure .11 thick and filed the corners just enough to lay it flat in the ID of the hammer. The original spacer was .16 so I will see what happens here shortly.
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OK So I shot 2 clips through the crony. Oddly enough the string climbed from 805 to 850 through 20 shots. I think Im on to something here but need to do a couple things to wrap my head around it.
First off I might go ahead and remove the bottle brush i crammed into the air cylinder :P and then I thin Im going to take the spacer down to like a .08 and see where I stand. My only goal is to be able to shoot the 18.13g JSB in a respectable group at 50-60 yards and decrease the group on the 21g H&N rounds. I think Im close to that happening here.
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So I have now began using Aluminum rod used for arrows and a pipe cutter for a better way to dial in the thickness of the spacer. Going for a .075 this go round :P
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So I have now began using Aluminum rod used for arrows and a pipe cutter for a better way to dial in the thickness of the spacer. Going for a .075 this go round :P
That is a winner. Shooting 810-795 over 20 shots. Will have to wait for Sunday to try and check a full string and how she is grouping but the 18.13g should do well at that speed all the way to 50 and 60 yards and the 21g even tighter
Maybe my wife wont notice me setting up a target in the back yard tomorrow while I'm supposed to be smoking the meat..
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I've had that result from removing the spacer before, but I didn't think anyone was interested in shooting 400fps,lol! It makes perfect sense that it would do that, so don't worry. When the spring is at minimum AND you remove the spacer you essentially make the hammer spring have zero preload. It is right on the edge with the spacer in place, remove it, and you you will get a big decrease. I remove the spacer on all my Hatsans and replace the hammer spring with a slightly longer one. That gives me a lot more tuning flexibility :D
Now, about the space you were concerned about with the "cylinder carrier" as Hatsan calls it. Don't worry about that at all. As long as it is secure, the space there doesn't matter a bit :)
I don't know that getting your velocity lower is going to help your grouping with the JSBs. Some guns just don't like them, and there's no way around it. None of my Hatsans have ever liked the JSB 18 grainers, which is why I shoot mostly H&N Barracuda Match(5.51 seems to work best in my gun). Back before Crosman changed their 14.3 grain domes, they were my go to plinking pellets and were very accurate(and cheap). Sometime in the last year, they changed their process, and now they don't shoot worth a poo in my guns :( I've measured 2 different tins lately, and the head sizes were all over the place.
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I had to do some heavy polishing in my at-44 to get the jsb pellets to shoot good. My hatsan looked horrible at the lead and TP. Not sure what they cut the lead with but it must have been a coarse rock :o JSB are very soft pellets and they were getting shredded by the very rough lead and burrs at the TP. After the polish job it shot JSB the best.
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So here it goes.. very strange results.. not what I had expected at all. Let me first say that m rifle must not have had a full charge when i ran it and got the 800ish FPS results on Friday. I expected a whole string off 800ish. As you can see from the following string I dont reach that FPS until nearly my 50th shot.
First shot on this string didnt register.
Created: 09-17-2017 11:42:29 AM
Description: .075 spacer 18.13jsb
Notes 1: 2900 to 600 PSI
Notes 2:
Distance to Chrono (FT): 3.00
Ballistic Coefficient: 0.031
Bullet Weight (gr): 18.130
Altitude (FT): 645.0
Temp: 61 °F
BP: 28.30 inHG
Shots
# FPS FT-LBS PF
89 610 14.98 11.06
88 637 16.34 11.55
87 649 16.96 11.77
86 654 17.22 11.86
85 693 19.34 12.56
84 681 18.67 12.35
83 702 19.84 12.73
82 715 20.58 12.96
81 721 20.93 13.07
80 730 21.46 13.23
79 733 21.63 13.29
78 742 22.17 13.45
77 749 22.59 13.58
76 752 22.77 13.63
75 757 23.07 13.72
74 766 23.62 13.89
73 770 23.87 13.96
72 777 24.31 14.09
71 778 24.37 14.11
70 789 25.06 14.30
69 790 25.13 14.32
68 795 25.45 14.41
67 804 26.03 14.58
66 801 25.83 14.52
65 802 25.90 14.54
64 806 26.16 14.61
63 811 26.48 14.70
62 826 27.47 14.98
61 810 26.42 14.69
60 816 26.81 14.79
59 815 26.74 14.78
58 813 26.61 14.74
57 809 26.35 14.67
56 809 26.35 14.67
55 806 26.16 14.61
54 810 26.42 14.69
53 808 26.29 14.65
52 805 26.09 14.59
51 800 25.77 14.50
50 795 25.45 14.41
49 796 25.51 14.43
48 786 24.87 14.25
47 790 25.13 14.32
46 786 24.87 14.25
45 775 24.18 14.05
44 774 24.12 14.03
43 776 24.25 14.07
42 778 24.37 14.11
41 768 23.75 13.92
40 766 23.62 13.89
39 769 23.81 13.94
38 764 23.50 13.85
37 758 23.13 13.74
36 755 22.95 13.69
35 750 22.65 13.60
34 751 22.71 13.62
33 741 22.11 13.43
32 738 21.93 13.38
31 731 21.52 13.25
30 719 20.81 13.04
29 727 21.28 13.18
28 713 20.47 12.93
27 715 20.58 12.96
26 713 20.47 12.93
25 703 19.90 12.75
24 710 20.30 12.87
23 701 19.79 12.71
22 703 19.90 12.75
21 677 18.45 12.27
20 690 19.17 12.51
19 690 19.17 12.51
18 689 19.11 12.49
17 682 18.73 12.36
16 676 18.40 12.26
15 669 18.02 12.13
14 673 18.24 12.20
13 670 18.07 12.15
12 671 18.13 12.17
11 660 17.54 11.97
10 665 17.81 12.06
9 654 17.22 11.86
8 650 17.01 11.78
7 639 16.44 11.59
6 653 17.17 11.84
5 641 16.54 11.62
4 639 16.44 11.59
3 639 16.44 11.59
2 632 16.08 11.46
1 630 15.98 11.42
Average: 734.62
StdDev: 59.36
Min: 610
Max: 826
Spread: 216
True MV: 742.73
Shots/sec: 0.07
Group Size (IN): 0.00
So I know this picture isnt pretty but 90 shots at 30 yarads did this and before any chnges I would have had a 12" diameter of shotgun splatter So I post this only to suggest there my be something to this
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So i'm thinking that if I can find a way to shoot the PSI range of #30 to #80 and see what that looks like on paper I may have what Im looking for. I didnt have any of the H&N 21g rounds to test but did shoot some 19 grain H&N snipers in tight groups. I expect the 21g will still be my better round with the JSB 18.13 being a pretty good plinker out to 40 yards.
I may increase the spacer from .075 to maybe .09 and see what happens. I didnt expect such a long gradual string..
Am I wasting my time with the whole spacer thing? I can always go back to stock and plug some valve ports like suggested but am very excited with the amount of shots and may tinker with it longer.
Thank you guys for your comments, I always appreciate the input.
In the end this rifle is for my two sons to punch paper and rattle metal drop targets.. So my Priorities in order Group, Shots per fill, and way at the end iS FPE
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You can either do a lower fill, or increase the hammer. It is that simple :) It is obvious that you have too little hammer spring.
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Thanks Rallyshark. I will first play with the fill and see what I get and then look to replace the spacer with one a little bigger. After that maybe plug some cylinder valve holes and see the effects. Maybe take a combo of 2 things to get a longer lower flatter FPS.
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Thought I would share a quick pic of the new spacer.. I just cant wait to get this thing sorted.
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Skip the spacer fiddling and start using the hammer spring adjustments. Much easier.
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Skip the spacer fiddling and start using the hammer spring adjustments. Much easier.
Last time you suggested that I had explained this particular rifle has very little adjustment in the hammer spring. Before any tampering I was able to barely get any reduction.. maybe to 860ish
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Great so now I'm happy with the results. Not perfect but a great plinker for the kids.
30 Yards with 19 grain 2800 PSI to 1400 PSI
Shots
# FPS FT-LBS PF
40 789 0.00 0.00
39 802 0.00 0.00
38 806 0.00 0.00
37 810 0.00 0.00
36 808 0.00 0.00
35 822 0.00 0.00
34 821 0.00 0.00
33 838 0.00 0.00
32 841 0.00 0.00
31 830 0.00 0.00
30 839 0.00 0.00
29 852 0.00 0.00
28 846 0.00 0.00
27 851 0.00 0.00
26 861 0.00 0.00
25 855 0.00 0.00
24 857 0.00 0.00
23 844 0.00 0.00
22 846 0.00 0.00
21 846 0.00 0.00
20 858 0.00 0.00
19 857 0.00 0.00
18 859 0.00 0.00
17 854 0.00 0.00
16 837 0.00 0.00
15 840 0.00 0.00
14 839 0.00 0.00
13 841 0.00 0.00
12 849 0.00 0.00
11 829 0.00 0.00
10 834 0.00 0.00
9 839 0.00 0.00
8 835 0.00 0.00
7 828 0.00 0.00
6 816 0.00 0.00
5 808 0.00 0.00
4 821 0.00 0.00
3 800 0.00 0.00
2 801 0.00 0.00
1 808 0.00 0.00
Average: 832.92
StdDev: 19.58
Min: 789
Max: 861
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That isn't a bad plinking string :) FWIW, your hammer spring must me stuck or something. You should have an easy 9-10 turns of adjustment.
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That isn't a bad plinking string :) FWIW, your hammer spring must me stuck or something. You should have an easy 9-10 turns of adjustment.
I just want to go about a 12 turn and the bold lunges forward on it. The results were so dismal with the adjustment I gave it up. I did notice there were plenty of black plastic articles inside the rifle when I broke it down to clean the first time. Perhaps there is an issue with where the rear of the spring rests? I dont know. I do know it acts nothing like my Hatsan Gladius where you turn it and see instant results. I was pretty sure though I had read where other people had similar complaints about not being bale to bring the rifle down to 800 via spring tension adjustment alone. Also assumed thats why many folks resorted to filling in the valve ports. I may still replace the stock spacer between the hammer and spring then plug Valve ports 1 at a time to see the results. Just not sure its going to get those pesky 18.13g to shoot any more consistently. I will wait for my new ammo to get here and witness the string for the 21gr before I take that plunge. I'm expecting tighter groups..would be nice to see a 1" group come together out to 50 but I suspect thats pie in the sky without shipping this off to a person and doubling my investment..lol.. not doing it
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I'm assuming you're inserting something into the hole in the hammer when you adjust the hammer spring? Otherwise, you're just spinning the hammer, and making no adjustments. That last string you posted needs more spring(CCW).
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So in order to get to the bottom of why the "normal" act of adjusting the spring tension wasn't working as it does on my other rifle or as others have suggested I took her apart again. I was surprised at how stiff the grub screw was until I removed it and saw the teeth. It took a great deal of force to remove and this would explain why the hammer would lunge forward even with a tool being used to block the hammer. Will clean this up maybe put an ever so slight dab of silicone on the threads put back to where it was in terms of depth into the hammer, reinstall the stock spacer and make another attempt at setting the rifle to the speed Im after shooting the pellets I prefer to shoot. Not sure how well this will work after seeing these threads. I may need another grub screw and even then the condition of he threads inside the hammer will be a question mark.. Sigh.. I guess the good news is I can always put it back to the way it was before this discovery and get 40 decent shots for plinking.
I measure about .006 less on the diameter where the threads are shiny. I will flush the threads inside the hammer, scrub the threads on the grub and hope for the best
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UPDATE:
After having contacted Hatsan regarding the condition of my Hammer and Grub Screw they promptly replied to let me know they are sending me a replacement for the both of them. Not long after that email I recieved a shipping confirmation. I must say Im very satisfied with their quick work on this. Makes me happy to be a Hatsan Fan.
I look forward to getting the new parts in and adjusting the spring tension like one would expect.