Pellet sizing - but up not down !!!

Discussion in 'General Airgun Chat' started by Lol Moore, Sep 21, 2013.

  1. Lol Moore

    Lol Moore Banned

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    Pellet sizing - but up, not down !!!

    Came across this and found it quite interesting amongst the plethora of info regarding pellet washing/weighing/sizing that is out there.

    https://www.youtube.com/watch?v=dwg_cqC1y-M

    I have played in particular with sizing and definately gained some extra consistancy in groups - note the word consistancy not necessarily accuracy. These are my recent musings on the matter, maybe totally wrong but worth discussing and investigating :confused:

    Now traditional sizing involves pushing the pellet through a very accurate hole so forming both the head and skirt into a smooth, round precisely sized diameter - the same diameter.

    Having thought about this a lot I think the relationship between sized diameter and the barrel is one of the key factors (amongst others) I think the point at which the air is applied to the skirt of the pellet so expanding it onto the barrel walls and into the rifling has to be consistant.

    Now the application of the puff of air is rendered consistant by the regulator and the hammer/valve, but the expansion of the skirt and initial movement of the pellet could be inconsistant if the skirts are not consistant.

    Imagine a slightly damged or oval skirt, yes some sizing will take place at the pellet is inserted but if there is even the tiniest gap at the skirt edge (inconsistant gap, not around the rifling) some of the applied air gets past the pellet before the skirt expands.

    Now traditional sizing will rendered this air gap consistant and could be one of the reasons it works, but the above video shows an interesting concept of increasing the skirt size so its bigger than the head, never seen that before.

    So what I need to do is size some pellets so head/tail the same diameter then flare the skirt so its bigger, maybe even big enough to mean it engages with the rifling when initially inserted.

    Has anyone tried pushing tight fitting pellets some way down the barrel before firing (not just in but well in)?

    Another thought I had whilst watching the pellets being pushed into my Airstream by the probe is does that design poo poo what I have just said, now the Airstream is a cut away breech so the pellet sits in a half diameter of the barrel so it could be damaged/deformed slightly when inserting, I think I need to use my Steyr for any of this flaring experimentation as the pellet there is inserted into the whole diameter of the barrel...mmmm:confused:

    I can feel a little project coming on :D
     
    Last edited: Sep 21, 2013
  2. Conor

    Conor Never been banned from sales Staff Member

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    Save your energy and time and don't bother with the experiment.

    Instead practise somebstanders with unsized pellets straight from the tin!;)
     
  3. Lol Moore

    Lol Moore Banned

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    Conor

    Its not all about just hitting the target :eek:

    I just like investigating stuff, I think this sort of thing is more pertinent to the bench rest guys where every tiny little micron of precision and accuracy has to be gleaned from the equipment.

    FT is a little bit more technique oriented in my opinion :rolleyes:


    I am brand new to FT and just getting to grips with sitting, slowly slowly catches monkey :p

    Off to Bisley next weekend for my first shots in anger on a FT course :eek:
     
  4. Woody

    Woody The Chaser!

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    You will enjoy the Bisley club shoot next week, speak to one of the club guys I am sure they will be more than willing to assist with your questions.

    In my personal view if you re not careful you can end up over analysing FT, but you have to find your own way - just make sure you have fun along the way.

    Seeing you live locally to me if you would like any advice I will assist where I can…..but I am not as technical as you my friend.

    Cheers,
    Justin
     
  5. Lol Moore

    Lol Moore Banned

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    Its in the chase

    Justin

    Thanks for the kind words, I may pick your brains and if I can help with any small simple machining jobs feel free to ask - I am no Jon H but can make/adapt at the basic level

    I agree totally about over analysing, particularly as I see with FT, you only have to hit a 25mm or 40mm hole - sounds easy :p

    I like to investigate the technicalities of shooting, and I like to design and machine "bits" I think there are those that investigate/invent and those that just get out there and do it ;)

    Spent most of today in my garden (lucky enough to have 53 yards down one side) and my ranging and sitting shooting is definately getting better - its not so uncomfortable now and I can group much better

    Really looking forward to next weekend :D

    I sometimes go down Ford ranges, funny place, I went yesterday and sat on the 100 yard range managed a group about 4" seated and it was breezy - good fun, the flight time is an age and with the light right I could see it most of the way down the range, huge loop :eek:
     
  6. Delphinus

    Delphinus New Member

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    There is nothing new here what you can see is that you can improve a little a pellet that doesn t work in a barrel, for me makes no sense spend time doing that.

    Buy different batches of a pellet that you like and find the one for your rifle.

    I don t know much but too much pellet manipulation is not a good thing.
     
  7. Lol Moore

    Lol Moore Banned

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    No, but

    Delphinius

    The point of the OP was really the interesting concept of sizing upwards which to me is new ;)

    I wasnt considering improving a pellet that doesnt work in a barrel only in seeing if the consistancy of an already precise and accurate setup could be improved even further - as I said probably more a bench rest sort of fine tune rather than a FT one

    Investigating stuff is never a waste of time if you have the time :)
     
  8. Tench

    Tench WHFTA World Champion 2016.

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    I taper ream my barrels so that where the pellet sits when it is positioned by the pellet probe there is no rifling and a perfect skirt to barrel seal, i have found this does tighten the velocity spread.

    If you load a pellet into most guns then remove the barrel with that pellet still in situ and look down the barrel you do see light around the pellet through through the rifling lands. this will lead to some air escaping past the pellet as the air pressure rises behind the pellet, this will cause inconsistency, ream it smooth with a reamer of the right dia that tapers down to below the i/d of the rifling lands just far enough to eliminate the rifling at the skirt saves having to size all the pellets and should achieve better results.

    Hand reamers have a .25mm taper over the first 10mm of length so are ideal for this.
     
  9. Lol Moore

    Lol Moore Banned

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    Tench

    I knew it, nothing is new ;)

    But surely if you can see light through the rifling then you ream down below the depth of the rifling the diameter where the pellet sits is now bigger than the pellet so air escapes around the top?

    Now if you did this taper reaming and also flared the skirt of the pellt so it was a snug fit in that taper that would be da'boss :p
     
  10. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    It depends on what you're trying to achieve here really and how you're measuring the results.

    It sounds to me like your theory could have merit. But are you concentrating your efforts on trying to achieve a more consistent muzzle velocity or are you trying to trying to achieve downrange repeatability (accuracy) ?

    Because one doesn't necessarily lead to the other. What you may end up with is deeper scoring from the rifling on your pellet skirt than you otherwise would have had without 'upsizing' your skirt and that may lead to reduced repeatability downrange.

    Forget about measuring muzzle velocity, instead you should measure downrange velocity to check your results. If you find greater downrange consistency, then move on to testing grouping sizes.

    When people say its a waste of time, what they mean is that the time you expend on this testing could be much better spent - if your ultimate goal is to knock down more targets in FT or HFT. I would agree 100% with that opinion.

    If you want to knock down more knock over targets, find a die/batch of pellets that group well straight from the tin buy lots of them and then shoot as many competitions as you can. When you miss a target make a mental note of why you think you missed and then use your time to practice not missing for the same reason again.

    Ask yourself how many World championships the guy in the YouTube video has won?
    Personally, I'd rather take advise from someone who can walk the walk.

    One of the best things about this sport (both FT and HFT) is that the people who are mega at it will go out of their way to give you truly helpful advise. Coner (former world champion) says he uses pellets straight from the tin, Cozy (current World champ) - straight from the tin, Ian Taylor (3 times world champ) - straight from the tin, Calps (he's won everything at one point or another) - straight from the tin, James Osbourne (former world champ) - straight from the tin.

    I could go on and on - but the pattern should be clear :D
     
  11. simona

    simona Active Member

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    I agree 100 per cent with Brian.

    The thing that concerns me with any sizing, lubing or preparation is that in any process (even just the additional handling of the pellets) there is potential for inconsistency or damage. If you make 99 pellets out of 100 fractionally better but make the the 100th a flyer.....

    I've only ever shot pellets from the tin. Suitable batches of JSB Exact will consistently group well under 10 mm centre to centre at 50 yards. Even the large weight variation (8.2-8.7 ish) does not have any measurable affect on performance in my gun; the velocity stays the same with the heavy and light pellets it's just the power that varies; they all land in the same place.

    I just finished second in the World FT championships, achieving the highest day score with 49 ex 50 on day 2. I also finished second at the 2011 world champs in Italy. The pure accuracy of the gun was not the problem in either case! Pellet prep entailed pealing red tape from tin.

    There is a lot to learn in FT but I think pellet fiddling is a dead end!
     
  12. Conor

    Conor Never been banned from sales Staff Member

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    No,
    I don't use mine straight from the tin, I remove the label first, pour into my pouch and then use directly from there ;)

    Calps uses his directly from the ground :D

    I once upon a time had a batch that were so super consistent weight wise on the pellet scales and through the chrono, I had the feeling I was into the MEGA batch...grouped indoors at 55yrds like a shotgun :eek::mad:

    HTH

    Conor (with 1 'n' and no 'e') :)
     
  13. Lol Moore

    Lol Moore Banned

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    To all

    I visit several forums and contribute when I feel I have something interesting to say :)

    I have obviously not made myself clear with this thread and I have obviously posted it on the wrong forum :)

    As I have already said twice in replies to others this sort of investigation is probably more suited to the BR guys and for me is more about scientific investigation rather than something to be done for HFT/FT competitions - there are simply too many other variables here to make this worthwhile.

    Brian - I agree totally with the comments about velocities Vs accuracy being two different things not absolutely fixed to each other, but they do relate closer to each other if you sort your pellets :rolleyes:

    Simona - I am not worthy ;)

    Oh, and just to clarify after lots of investigation into pellet manipulation what do I do - I use them straight form the tin!
     
  14. Conor

    Conor Never been banned from sales Staff Member

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    For your investigation to work,
    find a suitable batch of pellets that will hit a 20mm target at 55yrds benchrested every time indoors.

    Get a clamp/vice/gun rest that eliminates pilot error and recheck your batch accuracy. Shoot a few groups and take average size group with unsized pellets straight from the tin.

    Repeat process with your sized

    For the test to be fair, each and every pellet must be the same length, head diameter and weight. The barrel would need to be cleaned and leaded back in again accordingly before and after each test. Temperature, humidity and air density should be a constant also. The pressure in your rifles air cylinder should be the same before each test also.

    I eagerly await and look forward to your results.
     
  15. Lol Moore

    Lol Moore Banned

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    you know you do

    Written by a man who already knows the results ;)
     
  16. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    We're just trying to help you out matey, no need to roll your eyes at me virtually :) Actually what you'll find is that MV and accuracy very often have little to do with each other. One is measuring how consistent your gun is, the other measures how stable the pellet is in flight. Which was kind of the lost point in my earlier post - you're concentrating on getting a consistent puff of air up the skirt in the hope that it will deliver greater downrange accuracy when in fact you could very well end up making the pellet far less accurate downrange by pratting about with it and altering it's stability in flight.

    p.s. Has anyone introduced you to the idea of using an old BIC pen to sort your pellets yet? That's always good for killing a few hours, and trying to find an old BIC pen can become a good little hobby in itself :D
     
  17. Lol Moore

    Lol Moore Banned

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    Emoticons

    OK probably the wrong emoticon :eek:

    I will be more careful what I post on this forum in future, any "General Airgun Chat" discussions I want will be made elsewhere I will stick to FT/HFT here

    Not sure I am explaining myself very well I am always accused of rambling a bit, for example I said in my last response "I agree totally with the comments about velocities Vs accuracy being two different things not absolutely fixed to each other" you replied "what you'll find is that MV and accuracy very often have little to do with each other" is it just me.....(resist rolling eyes).....;)
     
  18. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    Perhaps if you quoted your complete sentence you might understand my response and save yourself some eyestrain from all that rolling ;)
     
  19. Lol Moore

    Lol Moore Banned

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    No, just re-read and still dont understand why you were repeating me ;)

    Anyway this pratt is off to do some pratting about :D
     
  20. Conor

    Conor Never been banned from sales Staff Member

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    I like pratt, harsher than pilchard, but still un-offensive none the less.:)

    Quit pratting about and get the results posted up here
     

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