1. The Forum Rules have undergone some minor changes and updates.  Please take the time to read them; it will only take a couple of minutes of your time. By doing so, you lessen the chance of incurring the wrath of the moderation team or making yourself look foolish to other members.

    90% of users posting adverts in the Sales forums need to be reminded to read the rules as their posts are wrong.  This is unnecessarily time-consuming and will no longer happen - if your advert doesn't follow the Sales Rules it will be deleted and you'll have to start all over again.

    To close this box once you've read it (and the Rules), click on the X in the top right-hand corner.

    Thank you.

    AGF Staff



    Dismiss Notice
  2. A reminder of one of the Forum Rules:

    'Behaviour

    Do not make inappropriate or offensive posts - including threats, harassment, swearing, prejudice, defamation, deliberate insults or name-calling, other negative remarks about this forum, its moderators and administrators or your fellow members. Even if this is just your own personal opinion, RESPECT YOUR FELLOW MEMBERS.'

    There have been changes made to our censoring software in an attempt to help with this growing problem.

    Click the X in the top-right-hand corner to dismiss this notice.
    Dismiss Notice
  3. Dear members,

    Our membership (like our country) consists of people from all walks of life; different in far more ways than can be listed here and each with a different view based on their experience of life - regardless of their colour, religion or cultural heritage. Every single person in the UK has been born of mixed race – we are a multi-coloured and multi-cultural country.

    As many of you are aware there are a handful of individuals amongst this membership that persist in making provocative, inflammatory, racist and otherwise offensive comments. This has been happening across the forum to a certain degree but is most especially prevalent in the Adult section.

    The moderation team has tried to stay on top of this, however unfortunately because of the ‘offensive’ nature of much of its content we don’t monitor the Adult section quite as much as perhaps we should. As a result much of this behaviour has gone unnoticed unless it has been reported to us. While the team always intended to take a "light touch" approach to the Adult section it would seem that some people aren’t quite adult enough to be left unmonitored after all.

    This behaviour is, and always has been against Forum Rules as well as the specific stipulations of the Adults forum and it will no longer be tolerated. We feel it's time to draw a line in the sand and as such from this point onward offenders will receive an immediate and permanent ban from the forum.

    In order for us to achieve our goal of restoring the forum to the friendly and tolerant place it once was, we ask that ALL members be mindful of the content they post and help us to stop unacceptable behaviour by using the 'Report' tool at the bottom of any offending post - the results of which can be seen only by Admin/Moderators.

    You should all receive a copy of this message by PM. 

    To close this message box, click on the 'X' in the top-right-hand corner.

    Dismiss Notice
  4. Hotmail block emails from us entering your inbox. Unless you can setup a safe sender you will not get activation emails from the forum. Please use an alternative provider or complain to Hotmail.
    Hotmail addresses include.

    @Hotmail.co.uk @Hotmail.com @outlook.com @Live.com
    Dismiss Notice
  5. Postings on Politics, Religion & Controversial Off-Topic Material

    The majority of users do not want to read about these subjects and people have left the forum as a result of it – this is after all an 'Airgun' Forum. It’s all very well to say they don’t have to read it if they don't want to, but as most of us use the ‘New Posts’ button there is no easy way to avoid it.

    All AGF staff members are in favour of people being able to discuss what they want, but we have to draw the line somewhere if it is upsetting other users. We don’t want to read about these topics either.

    IMPORTANT- The discussion of politics and religion is no longer allowed anywhere on the forum (including the Adult section).  The only exception is if it's airgun related - they must be put in the Airgun Related Politics section..

    We will not tolerate bullying or personal attacks, racism or any other offensive 'isms'. we will remove these topics from the forum, we will not give you an area where you can abuse each other. We will not hesitate to ban offenders.

    To clear this text box, click on the 'X' in the top right-hand corner.

    Dismiss Notice

Finding the sweet spot of my S400

Discussion in 'Anything Airgun Related' started by mattyts, Jul 14, 2014.

  1. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    With my Chrony finally hooked up to my laptop,thanks to Peter and his chrono cables,I thought it was time to do a few shot strings and find the sweet spot of my latest PCP.

    I didn't need the cable but automated recording of shots comes in very useful,writing them down gets incredibly tedious after a while.

    The gun in question is this one;

    [​IMG]

    It's an S400 Karbine superlite in a hunter green stock,.177 caliber,unregulated and completely stock.

    I haven't used it as much as I would like to so thought I better find the sweet spot before going any further with it.

    The sweet spot is the 'best' section of the fill in terms of the spread of velocity and power,where the guns internals are operating at their peak,part of calculating the sweet spot is finding a balance between number of shots and the spread of velocity,for example,usually the less shots you need,the lower the spread will be but as you need more shots,you use a larger portion of the shot string and as such,you are using shots that are more spread out.

    Ideally I want about 40 shots with a shot to shot spread of no more than 5-6 and an highest/lowest spread of no more than 10.

    I started by recording a whole shot string, filling to the maximum recommended fill pressure,200 bar and firing over 80 shots (81) until it was evident that the gun was running out of power.

    The shot string looked like this:

    (shown in chart and graph)
    [​IMG][​IMG]

    Now it's time to select the range of shots you want to use when your shooting,earlier I mentioned I wanted around 40 shots,I looked at the data and thought it would be best to use the group of shots from shot 27 to shot 69.

    Shown here,highlighted and circled:
    [​IMG][​IMG]

    This selection gives me 42 shots,which met my target.

    I also wanted my shots to have a shot to shot spread of no more than 5-6 and an highest/lowest spread of no more than 10,the shots I selected gave a shot to shot spread at the highest point of 6.56 FPS and a highest/lowest spread of 8.36,the shot to shot was slightly above the target but still pretty good for an unregulated carbine and the highest/lowest spread was within target,good news. ;)

    Now I know which shots I want,I have to find out what I need to fill my gun up to,to be able to start at shot 27.

    To do this,I fill the gun up to the same pressure that I filled it up to when I did the shot string,in my case this was 200 bar.

    Then I dry fire the gun 26 times to simulate shooting the first 26 shots,after I've done that I put the gun back on the bottle and read the pressure (opening the valve until the needle stops) which was 160 bar in my case.

    Doing this,I know that to start at shot 27,the start of my sweet spot I have to fill up to 160 bar and then I have 42 good,consistent shots which are all within 8.36 FPS of each other :)

    It might not be worth doing this if your just a plinker but if you are serious about competition shooting or want to get the best performance out of your gun without getting it regulated,this is one way to do it.

    I would be interested in how other peoples S400 Karbines figures compare to mine so if anyone has any full shot strings (starting at 200 or 190 bar) I would be grateful if you could send me them.

    Hope you have all enjoyed my little article/possibly tutorial and someone learns or takes away something from it.
     
    Lev Levvin likes this.
  2. trumpetier

    trumpetier Pro Poster

    Messages:
    6,268
    Likes Received:
    4,694
    Location:
    middlesbrough
    160 bar is were its at on my 400k in .177 40 good shots, also same fill presure on my 200 in .177, that gives 35 good shots
     
  3. cloverleaf

    cloverleaf Super Moderator Staff Member Mod/Admin

    Messages:
    21,768
    Likes Received:
    30,060
    Location:
    Oxfordshire
    A good write-up of a worthwhile exercise :)

    A couple of points:

    - What pellet were you using? It looks a little warm tbh (if this was with 7.9gn JSBs it'll be over with 10.34s).
    - A 160bar fill is low for a .177 carbine (which, on account of calibre and barrel length should favour a higher fill than other variants) - I suspect a new exhaust valve would sort this out for a time (how old is the gun?) .
    - Consistency looks good, but might be improved further by a hammer rail polish

    Sorry the only decent graphs I have of carbines are for .22s..
     
  4. Trouserferret

    Trouserferret Donator

    Messages:
    495
    Likes Received:
    0
    Location:
    Troon (Scotland)
    I don't have a bottle (yet), and I'm using a Combro but the method for this seems spot on.

    Need to see about getting the use of a Skan or an F1, but I think mine is around 170-150. Shoots a bit erratic at 200 'til it settles down and then it's anyone's guess where it'll end up at/below 140 @ 30m.

    I've a feeling the hammer spring needs replacing on my Falcon, which would contribute to this exponentially. But cheers for the infographic, dude. Much appreciated!
     
  5. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Thanks,the pellets I used Exact Express, 7.87gr,peaking at 11.38.

    The gun I have was made in 08/12 or at least the cylinder was.
     
  6. Cymru-Dave

    Cymru-Dave Donator

    Messages:
    1,524
    Likes Received:
    87
    Location:
    Pembrokeshire
    Good thread this, can this be carried out on one of the £50 combro's that fit to the end of the barrel?
    ive got the standard version and I'm interested to do the same on that.
     
  7. Ganton Gunner

    Ganton Gunner Super Duper Moderator Staff Member Mod/Admin

    Messages:
    12,842
    Likes Received:
    103,330
    Location:
    Ganton scarborough
    yes :)
     
  8. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Any chrono that will give a reliable reading.
     
  9. jw74

    jw74 Posting Addict

    Messages:
    1,327
    Likes Received:
    601
    Location:
    Camborne
    My s400 was filled to 170 and was sweet right down to 100.
     
  10. Cymru-Dave

    Cymru-Dave Donator

    Messages:
    1,524
    Likes Received:
    87
    Location:
    Pembrokeshire
    This is the range I use, however I've never tested it, it's just the values I stick between.
     
  11. Stevie Darling

    Stevie Darling Sexual tyrannosaurus

    Messages:
    18,690
    Likes Received:
    12,464
    Location:
    St. Andrews, Jockland.
    Nice write up matty:)
     
  12. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Thanks Stevie
     
  13. The Robin

    The Robin Super Moderator Staff Member Mod/Admin

    Messages:
    30,895
    Likes Received:
    11,475
    Location:
    Yorkshire
    Very interesting reading Matty, it's a well worth exercise on a un regged rifle (I've even done it on a regged rapid, I think I had chronoistis :eek:)
     
  14. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Thanks Simon, have the data here for my AA MPR too,trouble is it's over 140 shots from a 200 bar fill but on the upside I should get quite a lot of usable shots,I'm guessing around 70 but my bottle is due a fill because it won't reach 200 any more so I'll have to wait.
     
  15. The Robin

    The Robin Super Moderator Staff Member Mod/Admin

    Messages:
    30,895
    Likes Received:
    11,475
    Location:
    Yorkshire
    Great stuff Matty, you've got to have the stats :D

    I did it on my regged rapid 200+ shots, pen and paper and a crazy few hours recording it all .........:D
     
  16. Trouserferret

    Trouserferret Donator

    Messages:
    495
    Likes Received:
    0
    Location:
    Troon (Scotland)
    I think I'm only 60-70 usable shots (probably around 30-35 in their sweet spot) from my Prairie, and the thought of mapping them out with a Combro and a pen makes me baulk...
     
  17. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Did full shot strings with 3 PCPs and a 20 shot string of my springers by hand a few days before Pete told us he was going to do chrono cables :mad:
     
  18. Stevie Darling

    Stevie Darling Sexual tyrannosaurus

    Messages:
    18,690
    Likes Received:
    12,464
    Location:
    St. Andrews, Jockland.
    Are you getting good accuracy with jsb express,

    they are superb through my ultra:)
     
  19. The Robin

    The Robin Super Moderator Staff Member Mod/Admin

    Messages:
    30,895
    Likes Received:
    11,475
    Location:
    Yorkshire
    Its a killer but well worth doing in my book :D
     
  20. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Yes,I shoot them out of 2 springers and 2 PCPs,the MPR really likes them and can stack them on top of each other right out to 40 yard on a good day :)

    My ultra likes heavy pellets, weihrauch magnums,bis mags,crosman premiers...that kind of pellet.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice