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Reloading PSI

Discussion in 'Shooting Related Threads' started by blkfin, Feb 3, 2009.

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  1. blkfin

    blkfin Member

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    Just wanted to know if the psi relates to felt recoil if using the same shot weight. Mike K.
     
  2. setter

    setter Member

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    No, the formula for calculating recoil does not use PSI.
     
  3. blkfin

    blkfin Member

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    Setter, How would you find a lighter recoil load at 1200 fps 1-1/8 shot. Trial and error or is there a formula? Mike K.
     
  4. timb99

    timb99 Well-Known Member

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    No, if you are comparing one powder to another powder, where both yield the same muzzle velocity with the same weight of ejecta (shot plus wad) with different pressure values.

    Yes, if you're comparing one load with certain amount of powder "A" to the same load with a little more of powder "A", BUT the difference in recoil has more to do with higher muzzle velocity than the higher pressure.
     
  5. timb99

    timb99 Well-Known Member

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    "How would you find a lighter recoil load at 1200 fps 1-1/8 shot."

    Make it go slower (say 1150 fps) OR use 1 ounce of shot instead of 1-1/8 ounces.

    Its physics.
     
  6. setter

    setter Member

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    There is a school of thought that slower burning powders produce less felt recoil. For example; 7625 or PB would produce less felt recoil than Clays with the same load (1200 fps 1-1/8 shot).

    Edit - the website above may help clarify.
     
  7. blkfin

    blkfin Member

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    Setter, Thanks for the information. Been using 19.8 grns Green dot (not really to bad for recoil) but thought I would try something else. I'll try a slower powder and will try to stay around 1200 fps. Mike
     
  8. setter

    setter Member

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    See my note above.
     
  9. Shooting Coach

    Shooting Coach Well-Known Member

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    Some folks look at the book and say there is no difference in recoil between a slow and fast burning powder.

    Then, there are those who say felt recoil is less with a slower burning powder.

    I am of the latter group. I have a Handicap load with Unique that is very soft, but very fast. Try Unique for 1 1/8 oz loads at 1200 to legal max speeds, with Gold Medal hulls.
     
  10. phirel

    phirel TS Member

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    Mike- I can give a simple formula that is rather accurate. That is:
    velocity X weight of shot = amount of bump on your cheek.

    Powder burn rates and recoil-- The following two periods in this sentence are different sizes (. .). They vary by about 1/1000 of an inch. Can you see the difference? The size difference in these two printed symbols is much greater than the difference between a slow and a fast burning powder
    (+- 3/10,000 of a second).

    Pat Ireland
     
  11. hmb

    hmb Well-Known Member

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    Shooting Coach has it right and Pat is in a state of denial. There is a relationship, load up some shells and you be the judge. HMB
     
  12. blkfin

    blkfin Member

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    Thanks for the input. Looks like I'll have to purchsce some 1 lb jugs and see what happens using different components. Thanks again Mike K.
     
  13. jimrich60

    jimrich60 Member

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    To my mind, there are three "kinds" of recoil involved in a good target load. The first, of course, is actual or "real" recoil. This is a simple matter of physics and is determined by the weight of ejecta (shot/wad) and speed of that ejecta. It is determined by simple mathmatics. The second "type" of recoil is felt recoil. Determining factors are such things as gun weight, shape/fit of the gunstock, size of the recoil pad (if any) etc. A simple example of this is if you have ever fired the old M1903 Springfield rifle with both the original straight grip stock vs firing the same rifle with the later pistol grip "C" stock. Actual recoil with either is the same, but the "felt" recoil with the pistol grip stock is significantly less for most people. This also helps explain the current poplularity of the unsingle trap gun. The low position of the bbl puts the recoil in more of a straight line, resulting in less upward "kick" felt against the face, hence less felt recoil for many. The third "type" of recoil is what I call "perceived" recoil. This is purely a subjective feeling of recoil and is completely personal. It is here where, I think, you can place such things as powder burn rates. For whatever reason, some people "perceive" different powders as having less or more felt recoil. Although the physics of this are lacking, the perception of recoil differences can be valid for those who feel it makes a difference. For this reason, I would say go ahead and experiment with different loads. If you find one which you perceive as providing less or softer recoil, by all means, use it. It is unlikely you could actually measure much, if any, difference but if it "feels" better then it can only help your shooting. After all, many say that sport shooting is 99% mental in any case, so whatever helps your mental attitude towards more breaks can only be good for your game.

    Jim R
     
  14. hmb

    hmb Well-Known Member

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    It's the shooters that are mental, not the sport. HMB
     
  15. shot410ga

    shot410ga Well-Known Member

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    jimrich60, got it right.
     
  16. phirel

    phirel TS Member

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    Jim- I would not disagree with your comments. You also brought up the point that a shooters grip and arms absorb a lot of the recoil.

    Pat Ireland
     
  17. Shooting Coach

    Shooting Coach Well-Known Member

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    (snicker) "It's the shooters that are mental, not the sport"

    HMB has it right.

    Nobody noticed in my post that I said FELT RECOIL. The calculator may say that recoil is the same.

    My shoulder says differently at the end of the day. :^)
     
  18. halfmile

    halfmile Well-Known Member

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    Load 2 different loads, at the same velocity. One with higher pressure than the other.

    There will be no difference in recoil.

    HM
     
  19. Neil Winston

    Neil Winston Well-Known Member

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    Here are typical pressure time-courses that Pat is referring to. Note the time scale. I regret they look nothing like what you've seen in the imaginative hand-drawn graphs in trapshooting magazine but . . .

    <a href="http://photobucket.com" target="_blank">[​IMG]</a>

    <a href="http://photobucket.com" target="_blank">[​IMG]</a>

    Neil
     
  20. Shooting Coach

    Shooting Coach Well-Known Member

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    I still say Unique gives less felt recoil than most HCP powders. That's my story and I'm stickin' to it. :^)

    That Red Dot load looks wicked. Annie load or proof load? LOL
     
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