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Mapuia wrote:Hammer stroke 5.25 cw

If your Hammer throw is really more than one turn CW from 0, it is probably cutting out the o-ring buffer completely.

Not a bad tune, but it is just classic tuning - no Bstaley in the picture.

Ray

If im out of the bstaley tune, based on the A team tuning guide i can fine tune it with the valve metering screw?? Am i right If so does fine tuning flatten the shot string, increase efficiency and more shot count?

This is my latest modified Bstaley shot string which is good for hunting or plinking. I have the .22 Gen 2 Synrod. This string was shot using the JSB 18.13 pellets.

865
865
867
870
876
865
869
873
870
874
872
877
877
876
868
869
871
872
874
874
871
872
874
868
872
872
873
864
863
864

30 shots with a ES of 14 and a SD of 4.06 with a efficiency of 1.01 and a coefficient variance of 0.39%. My HS is 1.875 turns in and my HT is 2.125 turns in starting from full ccw. MY VMS is 5 turns out. Starting psi 3250 and ending psi 2250 using gun gauge. Average FPS is 870 and average FPE is 30.51. This setup achieved my goal of 30 shots at 30 FPE at 100% efficiency with a stock valve using the JSBs.

I used two 3/4" garden hose O-rings from Lowes that are the same rounded shape and O.D. as the #211 O-rings Bstaley used, but they allow me to shorten the hammer stroke a little more to get a little more FPS from a Bstaley tune. They also are thicker and have less bounce to them. The two stacked together are about 1/16" shorter than the three #211 O-rings stacked. I use a 10 pound spring and drilled my stock T-port out to 0.141" (9\64 bit) to allow for a little more air flow.

Your gun may be a little different as most are, but who knows you could get something close to this if you tinker with it. With this setup I'm able to shoot 1\2" groups flat out at 50 yards and maybe a little farther, but my backyard range limit is 50 yards. Hope this helps.

I got new sets of o rings and replaced the rings which i used before with a new it, i found out the the old orings were thicker and harder than the new o rings.
I filled it up to 2800 and here's my 50 shot string
1 767
2 778
3 776
4 792
5 798
6 800
7 795
8 790
9 792
10 802
11 792
12 809
13 804
14 812
15 809
16 814
17 802
18 820
19 814
20 814
21 814
22 804
23 817
24 809
25 814
26 802
27 809
28 804
29 804
30 797
31 800
32 814
33 804
34 809
35 804
36 792
37 804
38 804
39 802
40 792
41 800
42 797
43 790
44 785
45 780
46 774
47 774
48 769
49 767
50 758

Mapuia, I'm just curious if you are using any kind of grease on the hammer. Below is your string and it looks like your usable string is from shot 4 to shot 43, but the spread between some of the shots is too much or too jerky. I do not grease or oil my hammer, but keep that area very clean and dry.

How accurate are the JSB 18.13s shooting at those speeds with your gun? My experience taught me that they needed to be shot at around 850 FPS average to get the best accuracy out of them. What is your goal for the gun and these pellets?

Yes, as i was installing my orings I applied silicon grease and applied in the hammer as well, but find it difficult to cock so i dissembled it and wipe off the silicon grease. I am able to put one hole a bit larger than 1/4 inch smaller than 1/2 inch out of 10 shot group at 25 yrds. I have not yet tried a longer range as 25 is my maximum range available in my backyard. My goal was 50 shots between 2800-1800. I am using is for small game hunting pigeons squirrels etc. My max range is between 70-80 yrds

Well you certainly have achieved the 50 shot goal. Your accuracy is very good, and you have a good bell curve going on, all at your back range limit with a low power tune that is good for that range. I'm not sure what your settings are, but the Bstaley tune is geared toward a flatter than normal bell curve. Not knowing your settings, I would guess you are too many turns in on the hammer screw and off the o-rings based on the bell curve and extreme spread.

It is to easy to polish the hammer when you have it out. I use a VERY light coat of 10wt. silicone oil on the hammer. I have not had a problem with it yet.

Roger

Indeed i was too far on my hammer so i turn ccw a bit and it drop my max velocity to 814 and min to 790 same fill and same shot count. Im not sure my hammer settings right now it will be between 2-2.5 turns cw and hammer spring
2cw and valve open up to 5ccw

Wow, if that was for 50 shots that is a noticeable improvement. Your last string had a ES of around 70, and now only a 24 ES. The best setups have a ES of around 15 or less. Keep in mind a small change of 1\16" or 1\8" on the hammer screw can change the velocity a substantial amount on a Bstaley tune until you go off the O-rings.