AA S200 Bells & Whistles - Poor Results

[rabbitslayer]

IMPROVEMENT!.. but not there yet

After some helpful replies, info and advice from you guys today I went ahead with reducing the hammer spring tension. I wound the adjuster all the way out until the face was level with the breach block. Result as per below.

Air Arms S200 - .177
RWS Superfields - .177 8.4 Gn
Shot No: FPS Ft/Lb Pressure Check
1 782 11.42 190
2 784 11.49
3 786 11.53
4 780 11.35
5 780 11.35
6 781 11.39
7 785 11.51 180
8 785 11.51
9 784 11.46
10 791 11.67
11 784 11.46
12 785 11.51
13 790 11.65
14 790 11.65 170
15 793 11.75
16 788 11.60
17 791 11.67
18 786 11.83
19 790 11.65
20 788 11.58
21 788 11.58 160
22 789 11.63
23 791 11.67
24 786 11.53
25 788 11.60
26 788 11.60
27 782 11.42
28 784 11.49 150
29 790 11.65
30 784 11.49
31 786 11.53
32 790 11.65
33 788 11.58
34 791 11.67
35 788 11.60 140
36 786 11.53
37 781 11.39
38 784 11.49
39 781 11.39
40 783 11.44
41 784 11.46
42 785 11.51 130
43 788 11.58
44 782 11.42
45 785 11.51
46 785 11.51
47 789 11.63
48 789 11.63
49 787 11.56 120
50 789 11.63
51 788 11.58
52 789 11.63
53 789 11.63
54 790 11.65
55 795 11.79
56 792 11.72 110
57 792 11.72
58 794 11.77
59 790 11.65
60 787 11.56
61 790 11.65 100

What should I do next as shot count still not as high as I expected (60 fish total). Should I increase the firing valve spring tension slightly and should this then reduce air usage / increase shot count? Or.. do I start looking for a shorter than standard hammer spring? OR... is it 'suck it and see'

I'm also a little worried about power spikes especially when you look at those recordd at 110 bar and below. What is this telling me? power creeps up the closer the internal air pressure is to the regulator pressure setting?

All comments / advice will be gratefully received.

John

PS.

Sorry for the jumbled up data. There doesn't seem to be a way of importing / inserting a table.

[bezzer]

The "spike" at 110 bar is when it's coming off the reg , the gun settings you've got at the moment are working at their most efficient meanjng the reg is set a touch too high you get a few higher power shots then it drops right off.
Turn it down just a very small amount then do another string and see what that gives you. When you get a flat string you're at optimum reg pressure then you can start altering the other bits to get the power you want from that reg pressure

[rabbitslayer]

The "spike" at 110 bar is when it's coming off the reg

Don't understand what 'off the regulator' means.

The gun settings you've got at the moment are working at their most efficient meanjng the reg is set a touch too high you get a few higher power shots then it drops right off.

Do you mean the reg is currently set higher than 95 bar (indicated on the reg body), and is closer to 110 bar?

Turn it down just a very small amount then do another string and see what that gives you. When you get a flat string you're at optimum reg pressure then you can start altering the other bits to get the power you want from that reg pressure

What do you mean by a flat string... same FPS, no variation throughout the complete no' of test shots? Sorry if I seem thick

I was hoping I wouldn't have to touch the reg again. It's an internal reg and I hate pushing it past the internal cylinder threads. It's quite hard to push it past the threads and it feels like you're going to knacker the outer body 'o' ring on the reg. Ah well if needs must

[bezzer]

Falling off the reg means the main cylinder pressure has gone below the reg pressure so you're getting air at the same pressure either side of the reg i.e. the pressure has dropped below 95 bar and working as if the there is no reg there.

flat string = a string of similar velocities like you have been getting but that doesn't spike at the end just drops down.

Missed the fact it should be 95bar which is on the low side anyway for a .177, ignore me saying turn it down you can also eliminate the spike with the other settings, to save a load of typing and will be a lot clearer watch Rob Lane's video on what to do.https://www.youtube.com/watch?v=4gBFdY3YDxc

[rabbitslayer]

Falling off the reg means the main cylinder pressure has gone below the reg pressure so you're getting air at the same pressure either side of the reg i.e. the pressure has dropped below 95 bar and working as if the there is no reg there.

OK - I get that.

Flat string = a string of similar velocities like you have been getting but that doesn't spike at the end just drops down.

OK

Missed the fact it should be 95bar which is on the low side anyway for a .177, ignore me saying turn it down you can also eliminate the spike with the other settings, to save a load of typing and will be a lot clearer watch Rob Lane's video on what to do.https://www.youtube.com/watch?v=4gBFdY3YDxc

OK.

Going back to the reg setting. If it's falling off the reg at 110 bar, then this means the reg must be set at around 110 also and not at 95 bar? (sorry to repeat the question).

I'll watch the vid now.

Thanks for your help bezzer.

[bezzer]

Going back to the reg setting. If it's falling off the reg at 110 bar, then this means the reg must be set at around 110 also and not at 95 bar? (sorry to repeat the question).

Would appear so if your gauge is accurate, but the last overall string you posted isn't that bad really, you should get away with not having to mess with it just the other stuff - springs and hammer so you're using less air and getting an increased count.

[Geoff555]

Hello back again. I didn't want to complicate matters so I left this out.
On the .22 then having the screw flush with the breech block was too much and it was wound out about 1/8" further. I was not comfortable with this so I got a gas torch out , got 1 coil red hot and collapsed it. Screw is now flush with the breach block.
How old is the spring just as a matter of interest? Later I will measure a new one and come back with the length so you can compare it with what you have got .
ATB.
Geoff.