chrono test

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Hairybiker59
Posts: 181
Joined: Fri May 29, 2015 11:42 pm

chrono test

Fri Aug 28, 2015 4:01 pm

have just finished doing chrono test using un-weighed .177 h@n ftt.would you agree my sweet spot is 40 shots (shots 30-70)
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Mark112
Posts: 210
Joined: Mon Feb 16, 2015 5:25 pm

Re: chrono test

Fri Aug 28, 2015 7:38 pm

Hi,

I see power is back to a sensible level. What was the problem in the end? If you could post up those fps figures her in the form

767
768
759
etc

I can put it into my spreadsheet and give you some figures and a graph which me useful. Is this an older gun by any chance?

Mark

p.s. off to pub now so may be gone for some time ..
S410C .177 Regged - MTC Viper 4-16 x 50
S410K .177 Regged - Hawke Nite-Eye 4-16 x 50 AO IR
S410K .22 - Hawke Sport HD 3-9 x 50 AO IR
Logun Mk1 .22 - AGS 3-9 x 40
Theoben Taunus .22 - Simmons 4-12 x 40 AO
BW1911R2
Walther CP99
Webley Premier .22

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Hairybiker59
Posts: 181
Joined: Fri May 29, 2015 11:42 pm

Re: chrono test

Fri Aug 28, 2015 7:58 pm

Mark112 wrote:Hi,

I see power is back to a sensible level. What was the problem in the end? If you could post up those fps figures her in the form

767
768
759
etc

I can put it into my spreadsheet and give you some figures and a graph which me useful. Is this an older gun by any chance?

Mark

p.s. off to pub now so may be gone for some time ..

The problem was the barrel o ring,I replaced it and the power stayed the same so I changed it again and bingo,the rifle is indeed an older pre anti tamper.do you want me to list the full 70 shots chron'd or just the 40'i think that are the sweet spot

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Mark112
Posts: 210
Joined: Mon Feb 16, 2015 5:25 pm

Re: chrono test

Sat Aug 29, 2015 7:33 am

Hi,

All of the shots please to get the full picture. Start and end fill pressures would be good if you know them also. I base the sweet spot as being all shots that are within 1.5% of the maximum velocity recorded. I.e if maximum was 790 fps then any shot within 12 fps of that (778 and above) my spreadsheet shows all this stuff graphically. Your rifle seems to have a bit of a steep power curve like my .22 had before I replaced the main exhaust valve (an easy job for you as you already know how it comes apart). Anyway if I can do you a graph I'll show it here together with plots of 3 other S4** series rifles and you can decide if you are happy. I used to get 65ish shots in the sweet spot of both my .177 S400 and my newer S410 but they are classic length. You should be getting 2/3 of that i.e 40+ good shots in the sweet spot.

Mark
S410C .177 Regged - MTC Viper 4-16 x 50
S410K .177 Regged - Hawke Nite-Eye 4-16 x 50 AO IR
S410K .22 - Hawke Sport HD 3-9 x 50 AO IR
Logun Mk1 .22 - AGS 3-9 x 40
Theoben Taunus .22 - Simmons 4-12 x 40 AO
BW1911R2
Walther CP99
Webley Premier .22

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Hairybiker59
Posts: 181
Joined: Fri May 29, 2015 11:42 pm

Re: chrono test

Sat Aug 29, 2015 3:48 pm

Fill pressure 180 bar and I'm almost sure it was at 90-100 after testing

738
736
742
743
742
738
740
739
741
745
746
750
745
753
749
750
754
750
752
752
755
759
757
757
762
759
760
766
766
773
772
773
775
774
773
779
775
776
778
777
778
785
782
782
782
779
785
784
786
792
785
782
785
782
789
785
788
787
786
789
785
784
783
783
779
777
776
773
772
769
766
Has you can see from the last three shots power started to drop off

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Seamaster
Posts: 4
Joined: Tue Aug 18, 2015 9:13 am

Re: chrono test

Sat Aug 29, 2015 8:43 pm

From that Mike, I'd say you have 39 shots at an acceptable variance.
It may be that you allow more tolerance, (a greater velocity spread), so it's subjective.

Chris

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granville
Posts: 602
Joined: Sun Feb 15, 2015 7:33 pm

Re: chrono test

Sat Aug 29, 2015 9:09 pm

glad to see you have got the gun sorted .

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Hairybiker59
Posts: 181
Joined: Fri May 29, 2015 11:42 pm

Re: chrono test

Sat Aug 29, 2015 9:12 pm

Mark112 wrote:Hi,

All of the shots please to get the full picture. Start and end fill pressures would be good if you know them also. I base the sweet spot as being all shots that are within 1.5% of the maximum velocity recorded. I.e if maximum was 790 fps then any shot within 12 fps of that (778 and above) my spreadsheet shows all this stuff graphically. Your rifle seems to have a bit of a steep power curve like my .22 had before I replaced the main exhaust valve (an easy job for you as you already know how it comes apart). Anyway if I can do you a graph I'll show it here together with plots of 3 other S4** series rifles and you can decide if you are happy. I used to get 65ish shots in the sweet spot of both my .177 S400 and my newer S410 but they are classic length. You should be getting 2/3 of that i.e 40+ good shots in the sweet spot.

Mark

Waiting on you mark for the graph :D

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Mark112
Posts: 210
Joined: Mon Feb 16, 2015 5:25 pm

Re: chrono test

Sun Aug 30, 2015 5:52 pm

Just got in from a weekend on the lash followed by a day of harvesting and shooting. Working on graph now!
S410C .177 Regged - MTC Viper 4-16 x 50
S410K .177 Regged - Hawke Nite-Eye 4-16 x 50 AO IR
S410K .22 - Hawke Sport HD 3-9 x 50 AO IR
Logun Mk1 .22 - AGS 3-9 x 40
Theoben Taunus .22 - Simmons 4-12 x 40 AO
BW1911R2
Walther CP99
Webley Premier .22

no avatar
Mark112
Posts: 210
Joined: Mon Feb 16, 2015 5:25 pm

Re: chrono test

Sun Aug 30, 2015 6:51 pm

Hi

.... and here goes. This:-

HB_S410Carbine.jpg
HB_S410Carbine.jpg (150.04 KiB) Viewed 4215 times


.... is a plot of your power curve. Depends on how you quantify the 'sweet spot' but using a 1.5% rule (12fps as shown between the orange lines on the graph) would mean you only have 23 shots. Using a 20fps figure gives 40 shots.

Comapare that to my own S410 Classic:-

S410Classic.jpg
S410Classic.jpg (153.13 KiB) Viewed 4215 times


..... giving 63 shots within 1.5% and 87 shots within 20fps (if it were a carbine I would expect those figures to be 47 and 65 shots respectively). The following is my shooting buddies S400 Classic:-

S400Classic.jpg
S400Classic.jpg (154.22 KiB) Viewed 4215 times


.... which as you can see has a curve very much like my own one and gives a very similar figures of 64 shots (1.5%) and 88 shots within 20fps. Your curve looks very different. As I hinted in my previous text one of my own rifles had this type of curve and it was fixed by replacing the firing valve, pot spring and hammer spring. I may not have needed to change the springs but did it anyway as they are only a few quid from bgaltd on this site. A chap calling himself cloverleaf has done some research into deformation of the exhaust valve and you may want to search for "valve extrusion" on airgunforum.co.uk (sorry if this breaches any conduct rules moderators) as I think you may have this problem. I had a technical thread on the previous version of the airarmsownersclub which showed the before and after effets of replacing these parts. Sadly that info was lost when the site changed hands. Parts are relatively cheap and pretty simple to fit (you already have 75% stripped your own rifle).

Hope this is of some use to you and yes I know it is a bit geeky.

Mark
S410C .177 Regged - MTC Viper 4-16 x 50
S410K .177 Regged - Hawke Nite-Eye 4-16 x 50 AO IR
S410K .22 - Hawke Sport HD 3-9 x 50 AO IR
Logun Mk1 .22 - AGS 3-9 x 40
Theoben Taunus .22 - Simmons 4-12 x 40 AO
BW1911R2
Walther CP99
Webley Premier .22

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