s400 consistency

[wezdavo]

I was wondering if many of you have done the laborious task of chronoing shot strings to determine the sweet spot on your s400.

If you have, what was your fill pressure, fps deviation , shot count and refill pressure?

I am in the process of finding out mine, I have fully resealed it, polished the hammer rail and inside of the hammer, reassembled with no grease just the faintest wipe of light oil.

Firing pot is set to 57mm.

I have noticed that the transfer port has to be "quite a bit" choked to keep the power down to acceptable levels and for some reason it has a small 2mm preload? slip? washer on the hammer setup, is this normal? it does look factory..

My s400 is a carbine with classic cylinder and was anti tamper (all now removed).

I will update later after some experimenting..

[Mark112]

Hi,

The attached .jpg image shows the curve of my old S400 Classic in .177 calibre. It is standard apart from the hammer rail polish and new internals (valve/ springs etc). The two orange lines show the sweet spot (12 fps or 1.5% spread) and 64 shots are within that band when filled to 147 Bar. I only filled to 170 bar as a higher fill pressure results in low powered shots.

Mark

ShotstringS400.jpg (165.89 KiB) Viewed 7704 times

[wezdavo]

As promised here is the update.

Pellets used are AA field 4.52 straight from the tin unsorted..

155 bar fill.

1. 770
2. 772
3. 772
4. 782
5. 789
6. 778
7. 777
8. 782
9. 785
10. 781
11. 788
12. 783
13. 785
14. 775
15. 774
16. 778
17. 776
18. 778
19. 782
20. 782
21. 784
22. 779
23. 785
24. 787
25. 788
26. 787
27. 781
28. 778
29. 787
30. 775
31. 783
32. 784
33. 782
34. 786
35. 784
36. 780
37. 770
38. 781
39. 772
40. 776
41. 784
42. 774
43. 775
44. 779
45. 779
46. 788
47. 776
48. 775
49. 775
50. 777
51. 769
52. 771
53. 775
54. 772
55. 765
56. 772
57. 767
58. 761
59. 764
60. 761
61. 763
62. 759

Pressure left at this point was 105 bar when plugged into the dive bottle..

For unsorted unweighed pellets I am very happy with this, I am going to fill to 155bar and do 50 shot then refill which will give me 18 fps spread.

I think with sorted weighed pellets it would be fair to assume this would go down to 10 fps spread tops..

[Raj]

That is a mighty fine set of figures. The variance you see in the numbers will be quite indiscernible on the target.

[Geordie]

For a .177 I think that's quite a good string!. If your having to choke up the T/P so much, it might be beneficial to loose the washer on the hammer spring and make further adjustments via the firing pot. I think you could eek out more shots with a better variation.

My .22 s400 was returning better strings than many a regged rifle.

[poguemahone]

you said you re-assembled using the faintest wipe of light oil, do you mean on the hammer rail ???

[wezdavo]

For a .177 I think that's quite a good string!. If your having to choke up the T/P so much, it might be beneficial to loose the washer on the hammer spring and make further adjustments via the firing pot. I think you could eek out more shots with a better variation.

My .22 s400 was returning better strings than many a regged rifle.

I tried that first off but it struggled with the power at 155bar,even after winding out the pot 1mm at a time all the way to 62mm , started at 720 fps for around 15 shots before climbing to 760 fps so it would of meant an even lower fill pressure to get the consistency..

Do you think the variation is bad? remember this is pellets straight from the tin.

[wezdavo]

you said you re-assembled using the faintest wipe of light oil, do you mean on the hammer rail ???

Yes, but I mean a wipe with a rag not oiled as such..

[poguemahone]

you said you re-assembled using the faintest wipe of light oil, do you mean on the hammer rail ???

Yes, but I mean a wipe with a rag not oiled as such..

aye up davo, after polishing my hammer rail and valve stem, i leave them completely dry, and i know a few others on here do, for maximum consistency
only just put my s400 back together after a major problem with a leaking valve

[wezdavo]

you said you re-assembled using the faintest wipe of light oil, do you mean on the hammer rail ???

Yes, but I mean a wipe with a rag not oiled as such..

aye up davo, after polishing my hammer rail and valve stem, i leave them completely dry, and i know a few others on here do, for maximum consistency
only just put my s400 back together after a major problem with a leaking valve

I agree bud, I only wiped it with an oily rag to clean any remnants of the autosol polish... I reckon theres that little on there you would need forensics to find it

Was the fill valve not seating or summit in your s400?

I am liking these s400's, I was into falcons before this.. I managed to get my Prairie bb down to 10 fps spread over 100 shots with a bit of work but the valving on them is fantastic, even the hammer tube is lined with delrin on them and the power tuning is more straight forward to adjust making it easier to get a good balance between the valves.. Mine was a multi though and I like singles, had a single tray made up for it but because of the tiny mag slot it was just a pita so I sold it..

That said the s400 feels much better balanced with a nicer trigger..