The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores Pressure vs. RecoilGo | New | Find | Notify | Tools | Reply | |
Moderator |
in my experience if the powder charges are close, the "recoil" is close, but higher pressure, in the same weight gun, makes the recoil speed quicker. a la 2400 fps in rigby is slower to hit than 2400 in rem.. but, a 308 and a 3006, shooting the same bullet, in the same weight, at least SEEMED to be more in the 30-06 bc is has more powder? but I really don't think my shoulder has the intrumental resolution to tell you 2ft/lb or 2 fps. jeffe | |||
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| <Axel> |
I have shot both the Rigby and the Remington. To me the Remington kicked harder. I believe this is due to the Remington chambered rifle weighing less! Pressure should have a minimal effect on recoil I believe. After all since you are achieving the same end result the force acting upon the bullet must be comparable between the two cartridges. After all F=MA! I have shot different burn rate powders in my 50-110 to achieve the same muzzle velocity with less powder burnt. I could not tell a difference even when one load was 12 grains lighter than another. Muzzle velocity was 2100 with a 450gr bullet in both cases. Perhaps I suffer from Jeffeosso's lack of shoulder resolution as well. Axel | ||
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| Moderator |
quote:Again, it expresses a complete lack of knowedge. F=ma tells us nothing in, as time is not a component in that equation, except when V is known. what you are after, of course, is another force equation which is (in this case, call v2 as vel squared) F=mv2 when velocity is acceration over time. (v0 means v at time 0, in this case) velocity is v=v0+at, if you accept that F=ma can be rewritten to a=m/f then you can solve for v in which case you can solve F=mv2. aww, screw it.. i dont really feel like the physics lesson, but you solve for time, solve for force, and you'll have a statisical system that you can diagram into showing where velocity exists with various pressures, over time or volume. Or, simply, if you have 40k psi at X" past the chamber, there does exist a point where 55kpsi, again over time, can have the same results in the F=mv2 equation, as the specific expansion ratio of the powder and the mass of the gas will denote your acceration against a 400 gr bullet. great, and I haven't written these equations in 20 years. jeffe | |||
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| <500 Nitro> |
Mr MD, IMHO and this is only from my shooting experience with shooting Large Nitro Express Double Rifles (450/400, 450 3 1/4", 470, 500, 600) and Bolt Guns (375H&H, 458WM, 500Jeff, 505Gibbs) Where I have tried 2 different powders (one faster than the other) in the same gun, one after another with no other changes, the SLOWER powder seems to have less FELT recoil. All loads would have been approx 50 - 100fps less than maximum loads. I don't know enough about the physics side of pressure vs recoil to comment further and I do not have a pressure gun to test loads and unless you have this you don't have any factual data. Graeme Wright also mentions something in his book about felt recoil using different powders I also believe that way a gun is stocked is a major factor in felt recoil. Hope this helps in some way. 500 Nitro | ||
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| one of us |
The laws of physics require an equal and opposite reaction -- assuming bullets of the same weight, at the same speed, whichever gun requires more powder (which also exits the barrel, even though it's a gas, thus contributing to recoil) will have greater recoil. Other factors obviously play a large part, potentially much larger than the extra few grains of powder would -- stock shape and fit, drop, gun weight, etc. Todd | |||
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| <Axel> |
Jeffeosso, velocity squared is NOT acceleration! Acceleration is the time rate change of velocity. So a = dv/dt or simplistically speaking a = (vfinal - vinitial)/ (tfinal - time initial) The "letters" are: a = acceleration v = velocity t = time Conversely, we know what the force is from the relationship existing between force and pressure. Force is the time rate change of pressure times the cross sectional area of the rifle's bore. So F = (dp/dt)*A Where: p = pressure t = time A = cross sectional area of bore All this is pointless in that we are accelerating a mass to a velocity. Since the mass is the same and the final velocity is the same the FORCE IS THE SAME. Now if the powder charge is larger in one case than the other the mass is increased. The recoil force should then increase proportionally to the increase in total mass! This is precisely what Dr. Getzen has stated and he is correct. The that one cartridge achieve final velocity with a 60000 psi pressure, while the other cartridge achieve this same final velocity with 48000 psi pressure, is due to the area under the pressure versus time curve. This therefore dictates the time duration for a given applied force. Axel | ||
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| Moderator |
--double tap-- sorry [ 10-05-2002, 06:19: Message edited by: jeffeosso ] | |||
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| <Mr MD> |
Thanks 500 Nitro. That is the kind of anecdotal information I'm looking for. | ||
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| Moderator |
let me steal a line from ToddE this will be my last post...responding to this TrollE quote: | |||
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| <Axel> |
Jeffeosso, you are correct in that my understanding of Newtonian physics is very elemental compared to yours! You are way over my head. Could you answer one thing for me. What is actual factor determining the velocity, and therefore the acceleration, of the bullet? By the way, did you know that your equation; F=m*v^2 is exactly equal to twice the kinetic energy of the bullet? Axel | ||
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| one of us |
If you assume that higher pressure loads would generate a higher velocity of the gases exiting the barrel, along with having a greater weight of gases due to using more powder to produce the higher pressure; then you would have a reason for a higher recoil. I doubt that there is enough of a difference to matter, but someone who wants to spend the time might be able to calculate any difference. Once you start playing with faster/slower burning powders, pressure/time curves etc I think there is enough factors to warrent employing a full-time ballistics expert and lab for as long as your money lasts. | |||
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| one of us |
Had a friend that took pictures of det cord burn rates. Which do you think caused the greater damage, if confined, the 40 thousand feet per second, or the 120,000 fps? Put simply, high quality powders, in their area of expertise, cause higher velocity, with less recoil, then cheap powders that are often used by major ammo makers, cause they are cheaper. s | |||
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| one of us |
"I have shot both the Rigby and the Remington. To me the Remington kicked harder. I believe this is due to the Remington chambered rifle weighing less!" Could it be that the cheaper powders work less efficently, and therefore remingtion uses these powders, figuring that most people don't have a chronograph, and they associate a big bang, and tons of recoil with velocity, or power? Oh, and Remington also makes MORE MONEY using the cheaper powders? s | |||
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| <Axel> |
Socrates, your contention could be correct. Unfortunately, I can provide you with no proof of it. I have tried using faster and slower burning powders in my 50-110 to see the effect of a reduced powder charge on recoil. I loaded the hotter and slower powders to achieve the same muzzle velocity on the chrony. To be honest, even though the charge was as much as 25% different from slow to fast powder, I could not tell a difference in felt recoil. I guess if you think about it the mass differential of the fast versus slow powder is SMALL compared to the total bullet + powder mass. To put it bluntly I do not believe that a lighter powder charge, while achieving the same muzzle velocity, is going to be a real physical recoil reduction. Of course the mind is a powerful thing, if you think recoil will be lower perhaps it will! Doctor's have used this technique from time to time with documented results that, in my opinion, border on miracle. Axel | ||
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| one of us |
The bottom line to all this mathamatical jargon is you will have less recoil with less pressure, end of story... A 460 wby loaded to 458 balistics at 38,000 or so PSI will definately recoil considerbly less than a 458 win at the same velocity at its required 50,000 or so PSI, again end of another story ![[Razz]](images/icons/tongue.gif){kind=icon} | |||
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one of us |
Axel- What happened to the pathetic attempt to write like a non native english speaker. I was really impressed by that German auto engineer crap. The private message was a nice touch though! That and your total lack of knowledge of physics giving you away again? I frankly doubt you have ever fired a 50-110. Are you 16 ? Your really doing badly in the troll buisness. Time to re-invent yourself. My dog still wants a date! | |||
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| <Axel> |
Robgunbuilder, could you please explain to me how you hear my German accent in a verbal message? I speak fluent American. I have lived here for almost 16 years. I speak better American than German anymore. You really should be careful about your comments in regard to people's knowledge of physics. You reveal your own knowledge through these posts. Several of my colleagues at work today had a rather extensive laugh our your, and a few others on this forum's, expense. A couple of these gentlemen, were particularly fond of your Lexus and Detroit statements. Good day, Axel | ||
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| one of us |
Axel- you better re- read your previous posts where you tried the "I'm a poor foreigner routine who's english isn't that good". We all fell for that one for sure! Please at least be consisent as you go down in flames! We here, nearly died laughing at the Pecos45 and BBBABBLER responses to your pathetic posts! I nearly pissed my pants laughing so hard at you! You must work for Daimler-Chrysler. If it bothers you, I am even more pleased that I drive a Lexus. At least they have engineers who can build a car that works correctly and doesn't have to be recalled every two weeks! I believe the Japanese have minimum requirements for their engineering staff and actually do check their credentials. Sayonara- abunai Gaijin! | |||
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| one of us |
Axel: I think you have a point in one way. The heavier a gun, perhaps the less noticeable the difference is. Since my favorite shooting is heavy powered handguns, as Dr MD will attest, different speed powders can make a huge difference in comfort from the recoil you experience. I'll use one rather graphic illustration of this long ago. In about 1982 or so, I bought a 44 special bulldog with a 3 inch barrel. I was shooting alot at the time. My first lead 240 or 250 grain 44 special loads from Remmington gave a huge blast, huge recoil, and terrible accuracy. I had a very difficult time hitting center mass on a man size target, at 7 yards, and second shots were horrible. My guess is the loads started at about 700 fps out of a 6 inch barrel, and out of a three inch maybe, 500-600 fps. I went home, took 240 grain jacketed hollow points, put them over 9 grains of Unique, and had a gun I could use for head shots, with MUCH less recoil, and flash. I suspect the loads approached 950 fps and, I could shoot, and enjoy the gun. I did, and using that load, shot the gun loose in about 3 months. Bought a Detonics, 451 magnum, a high pressure version of the 45 acp, and never looked back. None the less, my reloads gave much higher speed, better accuracy, with much less recoil. I also suspect there are certain pressure jumps that occur with certain powders that create very violent, short duration, recoil. Heavy loads with Blue dot for instance, recoiled sharp, and hard. Suffice to say that each cartridge has a pressure area where you get reasonable recoil, and excellent preformance. When you try and hotrod any magnum cartridge, you enter an area of diminishing returns. You get higher velocity, but at the cost of possible bullet failure, and the recoil can start going up geometriclly as the pressure increases, with a linear increase in speed. In short, if the cartridge you are using requires super high pressure to accomplish what you want it to do, step up to a bigger caliber, at less pressure, if you can afford it. Strange thing about rifles is, this caliber selection is pretty much a process of natural selection, over the last 100 years. The 375 H&H is a standard because it works, at reasonable pressures. If you need something bigger, the 416 Rigby is the same, with a heavier, bigger bullet. From there it goes to what really should have been the 375 or 416 blown out to 458, the lott or AIM magnum, but, in the short run, a lot of guys bought into the 458 Win mag. I think that's a good example of a cartridge that will eventually die. As you go up the power ladder, the cases get bigger, and the bullets get wider, and heavier. Why? High pressure means a slow second shot, and that's usually more important, with DGR, then velocity. Your situation may differ. s | |||
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