Author Topic: Helpful tuning tips and links (Read 16883 times - 1 votes)
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oldpro · « **on:** February 17, 2016, 10:14:23 PM »

Im going to post some tips and links to help those in need of advise tuning their AG
http://www.calc.sikes.us/1/index.php
http://www.airgunsofarizona.com/energycalc.htm?fps=900&grains=55
http://www.calc.sikes.us/2/
http://www.airguns.net/calculators.php
Now the chronograph I use and Ill explain why shortly

And audio cable you will need

oldpro · « **Reply #1 on:** February 17, 2016, 10:18:13 PM »

First things first and thats setting up your Chronograph. I put mine indoors and shoot it outdoors threw a window in a safe direction into a pellet trap that also holds a standard size target paper. You can get different targets to print for free here= http://www.mytargets.com/ Now attach light kit to your chronograph and plug it in and remember chronographs hate artifical light so try to avoid it. If your going to data log with the supplied data cable DONT!!! Throw it away and use the cable I listed above or you will get many error or missed readings. Now its time to run a string

oldpro · « **Reply #2 on:** February 17, 2016, 10:31:46 PM »

When I run a base string I normally will fill to max fill pressure and shoot the gun down till its going to slow to be useful. I keep this data on my phone where its captured using the data cable from the chronograph, here in the app I can delete or modify the string adding pellet weight or deleting missed shots etc. After I run a base string I normally if more strings are needed will only shoot 1 pellet every 3 shots to conserve pellets until im close. Also remember that when running your string dry fire the first round always its a waste shot that will only screw up your string or misguide you Ill explain why later.

oldpro · « **Reply #3 on:** February 17, 2016, 10:56:53 PM »

Ok your chrono is set up with lights on and your ready to run a string so lets run one and see whats going on. Heres a string with a "Korean Cliff" that means its starts real fast and descends rapidly. The cause of this is normally to much hammer strike at the given fill pressure. Two ways to fix this or start to fix it, either fill to a higher pressure if its safe and run again or more likely reduce pre-load on hammer.
Created: 06/10/15 04:16 PM
Description:
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 0.054
Bullet Weight(gr): 31.00
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
8 906 56.51 28.09
7 917 57.89 28.43
6 930 59.54 28.83
5 940 60.83 29.14
4 945 61.48 29.30
3 953 62.53 29.54
2 971 64.91 30.10
1 977 65.72 30.29
Average: 942.4 FPS
SD: 24.7 FPS
Min: 906 FPS
Max: 977 FPS
Spread: 71 FPS
Shot/sec: 0.1
True MV: 944 FPS
Group Size (in): 0.00

Sent from my iPhone

oldpro · « **Reply #4 on:** February 17, 2016, 11:00:42 PM »

What we are after in a non regulated PCP is a smooth BELL CURVE. So what we are after is your starting shot being the same or near the same speed as your last shot in the string with the peek speed in the middle. This will give you the most shots in the target area and the best usage of air. Thus Lower ES and or SD. ES (extreme spread) isn't a total but the difference between the highest & lowest velocity in a string.
SD (standard deviation) is figure showing how close each load is to being alike.
Created: 08/08/15 09:47 AM
Description: bottled Flex .30 non Reg.
Notes 1: 3100 fill to 2400 finish
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 44.75
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
27 881 77.14 39.42
26 885 77.84 39.60
25 888 78.37 39.74
24 895 79.61 40.05
23 896 79.79 40.10
22 899 80.32 40.23
21 901 80.68 40.32
20 903 81.04 40.41
19 905 81.40 40.50
18 909 82.12 40.68
17 907 81.76 40.59
16 906 81.58 40.54
15 908 81.94 40.63
14 903 81.04 40.41
13 910 82.30 40.72
12 903 81.04 40.41
11 910 82.30 40.72
10 907 81.76 40.59
9 904 81.22 40.45
8 907 81.76 40.59
7 903 81.04 40.41
6 900 80.50 40.28
5 ERROR 10
4 896 79.79 40.10
3 896 79.79 40.10
2 893 79.25 39.96
1 888 78.37 39.74
Average: 900.1 FPS
SD: 8.0 FPS
Min: 881 FPS
Max: 910 FPS
Spread: 29 FPS
Shot/sec: 0.1
True MV: 900 FPS
Group Size (in): 0.00

Sent from my iPhone

oldpro · « **Reply #5 on:** February 17, 2016, 11:11:43 PM »

Anyone who wants to jump in here is welcome BUT please keep it as simple as possible Im doing this for those with limited tuning knowledge and LESS is more sometimes. You here me BOB LOL and you to Motorhead!!

oldpro · « **Reply #6 on:** February 17, 2016, 11:27:20 PM »

Ok lets look at some strings with problems and how I resolved them.

Description: .25 marauder stock reworked valve with SSG .187 barrel port
Notes 1: 2800-1800psi
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
23 895 45.19 22.73
22 889 44.58 22.58
21 891 44.78 22.63
20 890 44.68 22.61
19 916 47.33 23.27
18 891 44.78 22.63
17 906 46.30 23.01
16 908 46.51 23.06
15 908 46.51 23.06
14 912 46.92 23.16
13 912 46.92 23.16
12 903 46.00 22.94
11 903 46.00 22.94
10 910 46.71 23.11
9 895 45.19 22.73
8 912 46.92 23.16
7 898 45.49 22.81
6 887 44.38 22.53
5 909 46.61 23.09
4 888 44.48 22.56
3 883 43.98 22.43
2 900 45.69 22.86
1 903 46.00 22.94
Average: 900.4 FPS
SD: 9.8 FPS
Min: 883 FPS
Max: 916 FPS
Spread: 33 FPS
Shot/sec: 0.1
True MV: 900 FPS
Group Size (in): 0.00

Sent from my iPhone
The above string looks pretty good BUT every once in a while a much faster than normal shot would rear its ugly head!!! What gives? Well the first thing I would check in a string like this is hammer drag or binding. The hammer must flow smoothly down its bore to the valve if we want a string that is consistent. But in this case it wasnt that at all I had mixed two tins ofJsb pellets and some had thin skirts and some thick and when I put in the thin skirt pellet Id get a fst shot. SO when running your strings make sure your pellets do not have bent skirts or are different in any way.

Gertrude · « **Reply #7 on:** February 17, 2016, 11:31:42 PM »

Thank you Travis for your time and contributions for the benefit of all.
I'm sure many will find this helpful.
(I know I sure will) , subscribed so I wont miss anything you have to teach.

oldpro · « **Reply #8 on:** February 17, 2016, 11:36:50 PM »

Ok heres another problem string as you can see it starts off real slow then jumps up quickly. What gives? All air guns have a sweet spot where the valve likes to operate thus fill pressures can make a huge difference when tuning and air rifle and this is the most common cause for inconsistent shot patterns ive seen from customers guns sent in. The above gun was filled to 3K as described by the specs given by the maker( Crosman in this case but as you can see the valve is struggling to over come this pressure and open the valve and not till it dropped low enough in pressure was the pellet able to get up to speed. This gun was so far out of tune I stopped the string early.
Created: 08/14/15 11:38 AM
Description:
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 141.00
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
5 769 185.18 108.43
4 766 183.74 108.01
3 753 177.55 106.17
2 741 171.94 104.48
1 718 161.43 101.24
Average: 749.4 FPS
SD: 20.8 FPS
Min: 718 FPS
Max: 769 FPS
Spread: 51 FPS
Shot/sec: 0.1
True MV: 749 FPS
Group Size (in): 0.00

Sent from my iPhone

oldpro · « **Reply #9 on:** February 17, 2016, 11:39:36 PM »

I had my teaching credentials many years ago and was a 1st Grade teacher many light years ago. Thank you Sir.

oldpro · « **Reply #10 on:** February 17, 2016, 11:55:22 PM »

Ok back to business heres another string from a Flex .30 cal and im using a lot of Flex strings only because I have so many with varying results. In this case the Flex has a normal fill pressure of 3K but knowing that higher fill pressures in guns that can be adjusted to open the valve at high fill pressures will yield a tighter ES I filled it to test this out and as you can see at 3500 PSI its very efficient. But this isnt always the case it depends if the hammer energy is strong enough to open the valve at high fill pressures and the valve is able to flow enough. theres a lot more too it but Ill explain more in the advanced course lol.
Created: 07/29/15 01:14 PM
Description: flex 3500 fill
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 1.000
Bullet Weight(gr): 44.75
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
8 893 79.25 39.96
7 902 80.86 40.36
6 902 80.86 40.36
5 903 81.04 40.41
4 905 81.40 40.50
3 901 80.68 40.32
2 909 82.12 40.68
1 891 78.90 39.87
Average: 900.8 FPS
SD: 6.0 FPS
Min: 891 FPS
Max: 909 FPS
Spread: 18 FPS
Shot/sec: 0.1
True MV: 901 FPS
Group Size (in): 0.00

Sent from my iPhone

Tims229 · « **Reply #11 on:** February 18, 2016, 12:00:47 AM »

Hopping on to gain some knowledge. Thanks!

oldpro · « **Reply #12 on:** February 18, 2016, 12:08:07 AM »

When the numbers LIE. Sometimes the SD looks fantastic! But the truth isnt always in the SD and ES. Heres another Gun with a Fantastic SD but this gun was set up to shoot 200 Yards and If you look at the numbers you will see To much jumping from shot to shot and at those distances those points between the numbers can mean a complete miss. In this case the gun was shooting slugs and wasnt cleaned well and leading was the issue.
Created: 08/05/15 10:15 AM
Description:
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 0.540
Bullet Weight(gr): 54.00
Temp: N/A °F
BP: N/A inHg
# FPS FT-LBS PF
8 909 99.09 49.09
7 915 100.40 49.41
6 917 100.84 49.52
5 916 100.62 49.46
4 910 99.31 49.14
3 924 102.39 49.90
2 912 99.75 49.25
1 907 98.66 48.98
Average: 913.8 FPS
SD: 5.4 FPS
Min: 907 FPS
Max: 924 FPS
Spread: 17 FPS
Shot/sec: 0.0
True MV: 914 FPS
Group Size (in): 0.00

Sent from my iPhone

oldpro · « **Reply #13 on:** February 18, 2016, 12:35:04 AM »

When it all goes right. Ok you have all your mods done you shot your final string and its as good as you can get it. Sometimes there comes a time when a few points either way just doesnt matter much and you have spent far too much time shooting out into the pellet trap so Its time to call it. Heres a few tunes where I just couldnt eek out another point. I do not sort, weigh or lube my pellets I just dont have time so you will always see some inconsistency due to the pellets themselves.

Description: Flex .30 SSG HFP
Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 45.00
Temp: 67 °F
BP: 30.26 inHg
# FPS FT-LBS PF
20 888 78.81 39.96
19 887 78.63 39.92
18 888 78.81 39.96
17 892 79.52 40.14
16 892 79.52 40.14
15 897 80.41 40.37
14 900 80.95 40.50
13 898 80.59 40.41
12 887 78.63 39.92
11 894 79.87 40.23
10 898 80.59 40.41
9 894 79.87 40.23
8 895 80.05 40.28
7 892 79.52 40.14
6 898 80.59 40.41
5 896 80.23 40.32
4 893 79.69 40.19
3 893 79.69 40.19
2 893 79.69 40.19
1 891 79.34 40.10
Average: 893.3 FPS
SD: 3.9 FPS
Min: 887 FPS
Max: 900 FPS
Spread: 13 FPS
Shot/sec: 0.0
True MV: 893 FPS
Group Size (in): 0.00

Sent from my iPhone

Description: Steve
Notes 1:
Notes 2: .22 marauder build
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 0.00
Temp: 68 °F
BP: 30.01 inHg
# FPS FT-LBS PF
42 883 0.00 0.00
41 885 0.00 0.00
40 891 0.00 0.00
39 884 0.00 0.00
38 896 0.00 0.00
37 884 0.00 0.00
36 885 0.00 0.00
35 893 0.00 0.00
34 889 0.00 0.00
33 888 0.00 0.00
32 891 0.00 0.00
31 892 0.00 0.00
30 881 0.00 0.00
29 894 0.00 0.00
28 889 0.00 0.00
27 898 0.00 0.00
26 901 0.00 0.00
25 901 0.00 0.00
24 897 0.00 0.00
23 897 0.00 0.00
22 902 0.00 0.00
21 881 0.00 0.00
20 903 0.00 0.00
19 894 0.00 0.00
18 901 0.00 0.00
17 891 0.00 0.00
16 886 0.00 0.00
15 897 0.00 0.00
14 900 0.00 0.00
13 892 0.00 0.00
12 900 0.00 0.00
11 883 0.00 0.00
10 904 0.00 0.00
9 897 0.00 0.00
8 ERROR 10
7 894 0.00 0.00
6 897 0.00 0.00
5 898 0.00 0.00
4 899 0.00 0.00
3 884 0.00 0.00
2 903 0.00 0.00
1 884 0.00 0.00
Average: 892.9 FPS
SD: 6.9 FPS
Min: 881 FPS
Max: 904 FPS
Spread: 23 FPS
Shot/sec: 0.1
True MV: 893 FPS
Group Size (in): 0.00

Sent from my iPhone

oldpro · « **Reply #14 on:** February 18, 2016, 12:38:45 AM »

Now lets use one of those links to learn more about our fine job we did.
http://www.calc.sikes.us/1/index.php
Now take the Flex .30 above and put in all the specs with a fill pressure of 3k start and 2600 ending you will now get the efficiency per shot everyone is talking about these days. Now change those fill numbers from 3000psi fill to 2500 psi and you can see how much it changes.

oldpro · « **Reply #15 on:** February 18, 2016, 12:47:17 AM »

So what does this all mean? The more efficient you can make your gun the more shots you will get and the more accurate it will be and the report from the muzzle will be the quietest. This is what we strive for and why I stay up to midnight many days a week tyring to find those few points I couldnt find the day before. Im going to dig threw some crazy strings Ive had and see if anyone can figure out what was the problem .

oldpro · « **Reply #16 on:** February 18, 2016, 01:02:07 AM »

Ok if you were paying attention than you should be able to tell whats wrong with this tune. ANYBODY dont be shy its a learning experience.
Created: 10/16/14 11:04 AM
Description: WAR carbine
Notes 1: low speed tune HT 7 HS 0
Notes 2: 2900psi to 2400
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 0.00
Temp: 62 °F
BP: 30.05 inHg
# FPS FT-LBS PF
26 761 0.00 0.00
25 764 0.00 0.00
24 765 0.00 0.00
23 757 0.00 0.00
22 742 0.00 0.00
21 742 0.00 0.00
20 739 0.00 0.00
19 727 0.00 0.00
18 723 0.00 0.00
17 716 0.00 0.00
16 706 0.00 0.00
15 704 0.00 0.00
14 700 0.00 0.00
13 697 0.00 0.00
12 696 0.00 0.00
11 691 0.00 0.00
10 684 0.00 0.00
9 676 0.00 0.00
8 671 0.00 0.00
7 665 0.00 0.00
6 666 0.00 0.00
5 661 0.00 0.00
4 654 0.00 0.00
3 646 0.00 0.00
2 643 0.00 0.00
1 636 0.00 0.00
Average: 701.2 FPS
SD: 40.0 FPS
Min: 636 FPS
Max: 765 FPS
Spread: 129 FPS
Shot/sec: 0.1
True MV: 701 FPS
Group Size (in): 0.00

Sent from my iPhone

Motorhead · « **Reply #17 on:** February 18, 2016, 01:14:00 AM »

Descending velocity right out of the gate ..... YOU NEED A REGULATOR

You did say contribute

oldpro · « **Reply #18 on:** February 18, 2016, 01:22:14 AM »

Butthead LOL

Motorhead · « **Reply #19 on:** February 18, 2016, 01:39:27 AM »

Quote from: oldpro on February 18, 2016, 01:22:14 AM

Butthead LOL

What .... you saying string is ascending in velocity, what was I thinking !!!

You need a regulator !! ... still

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Helpful tuning tips and links

Author Topic: Helpful tuning tips and links (Read 16883 times - 1 votes) )

Author Topic: Helpful tuning tips and links (Read 16883 times - 1 votes)
)