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.38 spcl bullets; More speed=more pain.

Discussion in 'Handguns: Revolvers' started by 38snapcaps, Mar 24, 2010.

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  1. 38snapcaps

    38snapcaps Member

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    I made an interesting discovery and learned something this afternoon.

    For the four years I have owned my Airweight 642 I have mistakenly believed lighter bullets recoiled less, so I have been avoiding 148 and 158gr. cartridges. Usually I shoot 130's and carry Hydra-Shok 110. The Hydra-Shoks are very uncomfortable and a couple of cylinders was all I could stand to practice with. The 130's weren't much fun either, thirty-five rounds or so and I had to stop.

    I kept hearing about how nice 148 wadcutters were, so I bought some, and I found a good deal on Magtech 158 lswc ammo, so I bought a couple of boxes with trepidation, thinking boy are these going to hurt!

    I was amazed to find I have been completely in error about bullet weight. The wadcutters were quite enjoyable and the 158's recoil felt to be exactly the same.

    I looked up the specs:
    Magtech 158 lswc: 755 fps
    Winchester 148 wadcutter: 710 fps
    Winchester 130 fmj: 800 fps
    Federal Hydra-Shok 110 jhp: 980 fps

    Well, there it is, the faster the bullet the more hurt you're gonna feel. I'm going to be carrying the Magtechs from now on, heavier bullet, less recoil,
    better follow up shot ability. Oh, and I can practice with them more because they only cost $16 a box and don't beat my hand up.

    It's been a long trip but I truly enjoyed shooting my Airweight for the first time. I used to practice just out of necessity, never looking forward to the experience. That has all changed.

    I hope this range report will be of value to all you Airweight shooters.
     
    Last edited: Mar 24, 2010
  2. Fishslayer

    Fishslayer Member

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    I really like a 158gr LSWC over 3.9gr of Bullseye for .357 target plinking. Accurate & VERY soft recoil. Mind, it's in a 6" N frame S&W, not an Airweight. The load is essentially a +P (from Alliant's website) in a magnum case.

    You'd be surprised at the amount of increase in powder charge to get an extra 100-200 fps.
     
  3. rcmodel

    rcmodel Member in memoriam

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    In all likelyhood, you are getting closer to 600 - 650 FPS with those standard pressure loads in a snub-nose revolver. If the sun angle is right, you can see them on the way to the target.

    rc
     
  4. Vern Humphrey

    Vern Humphrey Member

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    Assuming the velocity figures are accurate (and if they are not, the difference is probably proportionate across the loads listed), if we take the 158 grain load at 755 fps as producing 100% recoil speed, the other three loads would produce 89.8%, 88.9% and 75.2%, respectively.

    Of course actual recoil is one thing and perceived recoil another.
     
  5. rmfnla

    rmfnla Member

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    "Well, there it is, the faster the bullet the more hurt you're gonna feel."

    Per given weight, yes.

    A 125 grain at 1250 fps will NOT recoil worse than a 158 grain at the same velocity.

    It's simple physics:

    F = MV or Force = Mass x Velocity

    This works for both ends of the gun. ;)
     
  6. BCRider

    BCRider Member

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    There's a thread about this same recoil issue on another forum I'm on. That one is getting a little heated between a couple of folks. In thinking about it and this one I'm not really seeing anything about the acceleration rate of the bullet. The other thread combatants are talking about impulse. And from the formulas they show the impulse is very close to the same when the bullets leave the barrel with the same energy. And that makes perfect sense if you look at it for overall impulse vs bullet energy. But in thinking about their equations and disscussions they didn't look at the time it takes for the bullets to reach their final speeds. And THAT is going to have a very big impact (excuse the pun :D) on the recoil felt by your hand. A light bullet that gets up to speed and leaves the gun super fast will feel a lot sharper than a heavy bullet taking a longer time to pick up speed and exit downrange. And I suspect this has a lot to do with how we perceive the impact pulse in our hand.

    And of course this goes totally against waht rmfnla just posted. But while that equation is 100% right it doesn't look at the time taken to ramp up to that speed.

    Rmfnla, you've made a basic mistake in your statement as well. I think you meant to say;
    Otherwise bullets of a different weight but same speed would be way different in energy and would certainly feel a lot different in recoil.
     
  7. Jeff H

    Jeff H Member

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    agree.

    I haven't followed that forum, but as an engineer, the speed it takes to get to a certain velocity has a direct relationship to recoil.
     
  8. oldfool

    oldfool Member

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    pretty much what Jeff said
    you can argue forever whether it is momentum or kinetic energy or whatever (force being mass x acceleration, action and reaction)
    but when all is said and done, it is how it feels in your hand, your grip, etc. etc.... felt recoil

    faster/lighter vs. heavier/slower, often does feel harsher
    even if some of the numbers may not suggest so
     
  9. Vern Humphrey

    Vern Humphrey Member

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    Correct. The faster bullet gets to speed quicker (since the barrel length remains constant). Or to put it another way, the acceleration for lighter, faster bullets is greater than the acceleration rate for heavier, slower bullets.
     
  10. 7.62 Nato

    7.62 Nato Member

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    I don't think it would be that simple. Otherwise a "blank" with a full charge of fast burning powder and fiber wad would have practically no perceived recoil because the fiber wad (projectile) would have only a few grains weight. If propellant type and amount didn't matter, rockets wouldn't fly.
     
  11. docsleepy

    docsleepy Member

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    for what it is worth, the equation is f= m a ; force = mass times acceleration.
    Newton however preferred to write it as
    force = rate of change of momentum
    which is the same
    momentum is m * v

    force = d/dt (m v), or another way to look at it is, the force exerted will be the momentum gained by the bullet divided the TIME in which it gained that speed. then you have to do some conservation of momentum stuff that basically says the heavier the gun, the less the recoil. Heavier bullets have more mass, less velocity.....it all gets rather tedious.

    For my snubbie, I put a tiny load of 3.0 grains of Win231 behind a 158 (I think) LSWC and get a speed of just over 500 fps for target practice. Zero pain. I just don't like pain. That alone sold me on reloading 38spc!!

    If I up it to 3.4 grains of Win231, the speed goes into the higher 500's and there is a small amount of felt recoil to me. ("to me!") Our family bought one box of +P, fired a couple, put the box down, and gave it away.....yep, we're just wimps. Standard 38spcc I can just tolerate, but for fun, I shoot these incredibly slow rounds. The ft lbs is down around 100, not the idea for self defense.
     
  12. Chumango

    Chumango Member

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    "In all likelyhood, you are getting closer to 600 - 650 FPS with those standard pressure loads in a snub-nose revolver. If the sun angle is right, you can see them on the way to the target."


    I have seen .22 LR from a 20" barrel on the way to the target when the sun angle was right (long distance target).
     
  13. bluetopper

    bluetopper Member

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    It's how much powder you put behind the bullet.

    The heavier bullet, the less powder you need to achieve the same chamber pressure.......if......the same pressure is your goal, and if, we are using the same powder.

    148gr cast lead wadcutters is all I buy, reload, and shoot anymore in 38. I see no need for any other.

    I reserve my 158gr cast SWC for 357.
     
    Last edited: Mar 27, 2010
  14. Old Fuff

    Old Fuff Member

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    I suspect that if 38snapcaps looks at his target he'll notice some improvement there too. Because the lead wadcutter makes a wicked wound at close range and the recoil is easy to control, I've used mid-range .38 wadcutters in small revolvers for longer then some members have been alive.

    They are particularly effective in my "parking lot gun, a lightweight Taurus .38 snubby carried in a pocket holster. I can keep my hand gripped on the gun without drawing or displaying it in public, in case a mugger or car-jacker decides that this senior citizen is easy pickings... :uhoh:
     
  15. Manco

    Manco Member

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    I finally decided to peek in this thread, and no offense intended, but boy is it a mess! ;) Although ultimately how recoil "harshness" is perceived is most likely an individual thing, I think that several posters here are on the right train of thought but we still don't have a good understanding of the issue. First of all, it is important not to over-think the issue. The most obvious factors are the average and maximum amounts of force transferred to the pistol over a period of time, right? Right, so plugging the numbers given in the original post for the heaviest, slowest and fastest, lightest loads, we get the following results (I could show my work but that would bore most people, and I won't even bother rounding to the significant digits):

    Magtech 158 LSWC (heavy and slow--just the way I like it, oh yeah)
    m = 0.01023822778 kg
    v = 230.124 m/s
    x = 0.1016 m
    a = 260615.43 m/s²
    avg F = 2668.2401353226454 N
    max F = 7569.4040578441668163209925194463 N
    t = 0.88300220750551876379690949227373 ms
    momentum = 2.35606192964472 kg*m/s
    E = 271.09319774878077264 J

    Federal Hydra-Shok 110 JHP (light and fast--the quickie round)
    m = 0.0071278801 kg
    v = 298.704 m/s
    x = 0.1016 m
    a = 439094.88 m/s²
    avg F = 3129.815657163888 N
    max F = 7569.4040578441668163209925194463 N
    t = 0.68027210884353741496598639455782 ms
    momentum = 2.1291262973904 kg*m/s
    E = 317.9892707678510208 J

    Legend: m = mass, v = velocity, x = barrel length (really delta x, the displacement), a = average acceleration, F = force, t = time in milliseconds, momentum happens to be equivalent to impulse in this case, and E = energy.

    Converting back to pounds of force because that's how we roll here, the average recoil force exerted by the 158 grain bullet over the 0.883 ms it spends in the barrel is about 600 lb, while the 110 grain bullet exerts an average force of about 704 lb over 0.68 ms. As is typical for most calibers, the load with the heavier, slower bullet imparts a greater reactive impulse (greater total momentum transfer) while the load with the lighter, faster bullet puts greater force on the shooter, albeit for a shorter period of time. Some may feel that the greater force of the latter "hurts" more, while others perceive the recoil of the former as being heavier and perhaps harsher to them as a result. Try a few different rounds and decide for yourselves.

    Not exactly in theory because bullet weight still matters, but that's how it pretty much works out anyway with most factory loads, so it's a decent rule of thumb for those in the "instantaneous force hurts more than total momentum" group.

    And in practice with most factory loads, too, even though the bullets are lighter, which results in less momentum. This kind of makes me wonder precisely how recoil should be defined--is it the average instantaneous force or the total momentum? Technically, I believe that it's the latter, but how we individually perceive recoil may beg to differ.

    The formulas are actually F = ma and I = mv (simplified for this case).

    Impulse (same as momentum for our purposes) is definitely a crucial factor, and I've included acceleration and the resultant amounts of force above to help complete the picture.

    Note that for a given caliber, a factory load can have greater energy but lower impulse than another factory load at the same time.

    Yes, and I suspect that force is more significant for many people.

    That's because there are two often opposing ways to gauge the perceived harshness of recoil--both of which are valid and feel different--as I hopefully managed to describe above.

    Ah-ha! You just mentioned energy. Note that from the numbers I gave above, the relative energy of the two loads varies proportionally with their relative amounts of force. This is true from the underlying equations because the amount of displacement--in this case the barrel length--is the same 4" that is typically used to derive the published specifications of .38 Special cartridges. Energy is merely the amount of work, which is defined as applying a force over a distance, that is done on both the bullet and ultimately your hand. The greater the amount of energy involved, the harder your hand gets worked over, so to speak. ;) That's why for some people the greater energy that comes from greater force hurts more than the impulse/total momentum/recoil/whatever you want to call it. Those guys in the other forum know what they're talking about regarding recoil by the numbers but they're not seeing the whole picture.

    And in addition to everything I've said, higher-pressure rounds tend to feel harsher to many people as well because they have a higher maximum or peak force. Most of us are already familiar with this phenomenon and refer to it in terms of "snappiness."
     
  16. oldfool

    oldfool Member

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    yeah, what Manco said
    (engineers, I-R-1-2)

    or... you could just drop a "same" weight (125 gr for example) 38sp, followed by a 38+P, followed by a 357, in an airweight snubbie cylinder, and fire 3 in a row real fast, and find out real faster that faster hurts more
    my guess is that you will "know" right away that the extra weight of 158 gr vs 125 gr just ain't going to make your day, no math required

    "speed kills"
    ;)
     
  17. Manco

    Manco Member

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    I should have mentioned that you had already nailed the whole issue down rather succinctly here, and I was really just doing some legwork and explaining things in more detail with hard numbers to back it up.
     
  18. BCRider

    BCRider Member

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    Manco, you're right about this being somewhat subjective. And your post provides much to think about.

    In addition to modern semi and revolver smokeless loads I'm also enjoying shooting black powder cap and ball revolvers. And one of the group let me try out his Colt Walker a few weeks back. There's a very large push and the gun lifts the muzzle in a very satisfying way. But it's not harsh. To try to compare it to shooting .44Mag it's like a .44Mag is like someone hitting the end of the barrel with a well aimed swing from a baseball bat. But the black powder recoil is more like a large bouncer giving the gun a serious slap/push. The energy is still there but without the snap to it. But I can see how some may prefer one over the other. But there's no doubt that less muscle, joint and nerve damage will be done with the longer but maybe harder push than the short but intense slap.
     
  19. Ky Larry

    Ky Larry Member

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    Remember you highschool physics class: Force= Mass X Acceleration.
     
  20. Manco

    Manco Member

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    Right, it's often helpful to look at extreme cases like this. You've just showed that the amount of energy involved only tells you how the recoil will feel, relatively speaking, for a single caliber and for that matter a single handgun. Other comparisons are only meaningful to the extent that the handguns are similar. Obviously, the original post only dealt with different loads fired from the same handgun.
     
  21. evan price

    evan price Member

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    f=ma is true for force, but for kinetic energy the formuls is E=1/2 MV^2
    (One-half times mass of projectile times velocity squared)

    So you see velocity affects kinetic energy much more than mass does.
     
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