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Thread: CRAP AA S400 Shot Count

  1. #1
    Join Date
    Mar 2017
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    Thumbs down CRAP AA S400 Shot Count

    Evening all

    Just did my first Chrono on my S400 Carbine and was pretty shocked with the results of the shot count! I filled to 180 bar from the reading on the fill bottle (cannot trust the AA gauge). On a 45 shot count the avg FPS was 766 and the PDS was 10.9. However, after just 33 shots the FPS dropped like a stone going from 766 FPS at 33 shots to 740 FPS at 45 shots. Is this normal? I shoot 30 target HFT and this wouldn't be enough to see me through a course, when you I have experienced up to 7 stoppages on a shoot recently! If I up the fill to 190 bar, would this make FPS more unstable, will I get a better sweet spot? I was surprisingly disappointed that 180 bar fill wouldn't even see me through an HFT shoot.
    Any advice greatly appreciated!

  2. #2
    Join Date
    Aug 2000
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    Crawley, West Sussex, UK
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    It's not a direct comparison, but it might help a little : my BT Reg'd 0.177 cal AA400 Carbine runnng at 11.4ftlbs with H+N Field and Target Trophy Pellets gave me 65 good shots before falling off the reg.

    With one of my other unregulated AA400s, I found that slight downward adjustment of the power setting gives a reasonable increase in shot count, from memory, maybe twenty further good shots for a ME reduced by 0.25ftlbs or so.

    Possibly jugging around a few of the settings might help a little, and checking for leaks in the Transfer Port and Barrel Seal area might show up something causing detrimental performance.

    HTH, Vic Thompson.
    Last edited by Vic Thompson; 12-11-2017 at 06:13 PM.

  3. #3
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    Mar 2017
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    Thumbs up

    Cheers Vic. Will check for leaks first as i'm not confident about messing with power settings (I think these are anti tamper!!) I really like the pellets i'm using, Daystate Rangemaster Soverign with really tight groups at 30yds. Worst case scenario for HFT shoots...I did another test today and filled to 190 - 195 Bar and got an extra 10 good shots before it started to dip significantly. I did notice that with so much pressure from the fill, the first 5 shots were normal (approx 765 fps) then it started to climb to 775 fps and stayed relatively consistent for from shot 7 to 37. I guess the valve is under a little too much pressure in the beginning and takes time to relax after a few shots. At least I am getting about 40 decent shots at 190 - 195 bar fill and if I discover a leak then this will be the source of the original disappointment.

    One final question....is it worth regulating?

  4. #4
    Join Date
    Aug 2000
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    Crawley, West Sussex, UK
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    "One final question....is it worth regulating ?"

    Not in my opinion based on a sample of one/two, namely my AA400 Classic BT tuned. This gave me around 120 shots or so at around 10.5 ftlbs with around +/- 1.5 % MV variation (from memory). As far as I can see someone who is prepared to invest time setting up an AA400 to run at 10.5 ftlbs or so (via adjusting Hammer Spring Set Up/Venturi Set Up etc) can save themselves a lot of money and achieve results all but as good as those obtained by fitting a regulator (and a colleagues BT AA400 also performed ditto),

    JMHO, Vic T
    Last edited by Vic Thompson; 12-11-2017 at 06:39 PM.

  5. #5
    Join Date
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    Kloppville- 10,533 miles from Lake Mulwala.
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    7,089
    Quote Originally Posted by KJMCMENA View Post
    Evening all

    Just did my first Chrono on my S400 Carbine and was pretty shocked with the results of the shot count! I filled to 180 bar from the reading on the fill bottle (cannot trust the AA gauge). On a 45 shot count the avg FPS was 766 and the PDS was 10.9. However, after just 33 shots the FPS dropped like a stone going from 766 FPS at 33 shots to 740 FPS at 45 shots. Is this normal? I shoot 30 target HFT and this wouldn't be enough to see me through a course, when you I have experienced up to 7 stoppages on a shoot recently! If I up the fill to 190 bar, would this make FPS more unstable, will I get a better sweet spot? I was surprisingly disappointed that 180 bar fill wouldn't even see me through an HFT shoot.
    Any advice greatly appreciated!
    Hmmmm...summat not quite right here.
    My 400k will do around 2 HFT courses on a 190 bar fill.
    Here be my chrono readings......taken a while ago mind, but!!!



    HTH.

    Roy.
    If it moves.....shoot it!..If it don't move.....shoot it in case it tries to!!!
    Light travels faster than sound....this is why I appear bright until you hear me speak!!!

  6. #6
    Join Date
    Jan 2016
    Location
    Ashby-de-la-Zouch
    Posts
    939
    My girlfriends s400 carbine is set at around 11.5 ft-lb. Action is standard

    I did a 60 shot string last week from a 180 bar fill
    - First 5 shots were about 11 ft-lb
    - next 5 ramped up to 11.6 ft-lb
    - next 40 shots all within 10 fps of eachother, from 780 - 790 (11.4 - 11.7 ft-lb)
    - next 10 quickly ramped down again to 10.5 ft-lb where I stopped

    Those first 10 lower power shots don't seem to make any difference when zeroing at 25 yards.
    So we fill to 180. 10 shots at zero range
    Then got a full course worth plus 10 extra shots for stoppages or clearing pellets

  7. #7
    Join Date
    Mar 2011
    Location
    Macclesfield and Ely
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    1,065

    160 bar max fill

    160 bar max fill in an AA S4** as the high pressure makes the valve hard to open.Thus resulting in lower fps.Anti Tamper sockets can be obtained online for a couple of £. Basically star drive with hole in center.Just picked up a gun cheap as it was doing 6ftlbs !! Anti tamper had worked its way down.5 mins later it's 11.4 !!!!
    Also if shot count is down check if an FAC hammer has been fitted as this can drastically reduce shot count.And or if shims to pre load hammer spring have been fitted.

  8. #8
    Join Date
    Feb 2009
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    If you bought the rifle new I suggest you take it back to the dealer to be sorted rather than diving straight in.
    OAKS - SIHFT Winners 2011, [SIZE=4][COLOR="#FF0000"] 2012, 2013, 2014, 2015, 2015, 2023

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