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.40 loaded to same as .45 acp = same power?
- Thread starter HighValleyRanch
- Start date
Aguila Blanca
Staff
I think that 5.3% is well within the range of experimental error. Consider that a Ransom Rest doesn't have any way of measuring movement, and the inserts that hold the gun are slightly soft. To measure movement requires setting up some sort of external Rube Goldberg apparatus to try to quantify how far up the gun flips in the Ransom rest. I doubt very much that three strings of five or seven shots each fired out of the same gun would register less than 5.3% difference.44 AMP said:A whole 5.3%?? wow!
Doubt I could notice that without test equipment, doesn't sound like something I would seriously concern myself about, I think.
I think that 5.3% is well within the range of experimental error. Consider that a Ransom Rest doesn't have any way of measuring movement, and the inserts that hold the gun are slightly soft. To measure movement requires setting up some sort of external Rube Goldberg apparatus to try to quantify how far up the gun flips in the Ransom rest. I doubt very much that three strings of five or seven shots each fired out of the same gun would register less than 5.3% difference.
Measuring movement with a RR looks pretty easy. Just measure how far the rocker arm/gun moves. A simple ruler works.
https://www.shootingtimes.com/editorial/measure-relative-handgun-recoil/99442
I've lots of experience with a RR. The inserts hold the gun firmly in place, and it's not subject to moving back and forth when the gun fired then reset to the start position. The recoil always pushes the gun to the rear, and there is a special tab on the rocker arm to push the assembly back down to the start position, so there is no force applied to the gun to push the gun forward.
The article above shows some of the actual movement data, and it correlates extremely well with recorded velocity. It can distinguish between different gunpowders and different charge weight of the same gunpowder.
Which is why the mass of the powder (while theoretically a factor in recoil) is usually ignored when calculating the recoil of pistol cartridges.
According to who?
The difference in recoil between powders can be significant. In the article below they found a 20% difference in recoil between N320 and A#7. See table 1.
https://www.shootingtimes.com/editorial/measure-relative-handgun-recoil/99442
"Usually" isn't according to "someone", it's a statement about the ordinary.
If you think it's worthwhile , you can do a random survey of a significant number of references to handgun recoil and see how many of them talk about powder charge vs how many don't and see if my comment is correct or not.
If you think it's worthwhile , you can do a random survey of a significant number of references to handgun recoil and see how many of them talk about powder charge vs how many don't and see if my comment is correct or not.
It is only ignored by simpletons. Ballisticians, Engineers, and those who know, include the powder mass within the term "ejecta" which is the sum of the powder and bullet, wad (if used) in many formulas. Other times it is broken out as a separate variable. It is not "theoretically" a factor, it IS a factor. Just because non math types ignore it does not move it from an actual variable needed for accurate calculation to "theoretical". It was proven, thus, not theory, long before any of us were alive.Which is why the mass of the powder (while theoretically a factor in recoil) is usually ignored when calculating the recoil of pistol cartridges.
Power Factor is a grossly simplified version that is not even accurate. It is more for relative comparison and to aid in simple calcs for competition.
Even the simplified velocity formula includes it...
Vf = (Mb x Vb + Mc x Vc)/1000Mf
Vf is the firearm velocity and the other variables are Bullet Mass, Bullet Velocity, Mass of Charge, Velocity of charge respectively
Jim Watson
New member
Coming up with a number for Vc is the trick.
I have seen various multiples of Vb and arbitrary numbers as high as 4500 fps.
Has a highly instrumented ballistics lab measured the "uncorked" gas jet to get a value?
Long ago I saw an item with a gun suspended on strings to form a ballistic pendulum, overall recoil was actually measured.
I have seen various multiples of Vb and arbitrary numbers as high as 4500 fps.
Has a highly instrumented ballistics lab measured the "uncorked" gas jet to get a value?
Long ago I saw an item with a gun suspended on strings to form a ballistic pendulum, overall recoil was actually measured.
Aguila Blanca
Staff
A simple ruler doesn't work, because a Ransom rest doesn't move in a linear direction -- it rotates. Sure, you can use a protractor of some sort mounted beside the Ransom rest, but that requires making a precise visual alignment with something that's not part of the actual Ransom rest. That's why I said that 5.3% is within the margin of error for however you are attempting to measure the movement.74A95 said:Measuring movement with a RR looks pretty easy. Just measure how far the rocker arm/gun moves. A simple ruler works.
I have had a Ransom rest for years. I feel absolutely certain that it's not possible to quantify the recoil movement to within 5% accuracy/precision.
And, the wheel turns, which brings us back round to whether or not a small, calculatable via formula or manually measured, difference actually makes any practical difference.
Personally, it makes no difference to me what a gun does, fired in a ransom rest.
A) I don't have a Ransom rest, B) even if I did, its not something I can carry around and us, and C), its not ME SHOOTING the gun. I suppose it's somewhat useful as a standard to make relative comparisons between guns, or loads, but that doesn't mean what happens in the rest will happen in my hands, or whether or not I can even notice it is happening.
Particularly with small amounts of difference.
Argue all you want, the math says (with ALL factors taken into account) one is slightly less than the other, or its not, depending on how the numbers work out. (GIGO)
Whether it makes any difference to the person shooting, or what gets shot, is a different matter, I think.
Personally, it makes no difference to me what a gun does, fired in a ransom rest.
A) I don't have a Ransom rest, B) even if I did, its not something I can carry around and us, and C), its not ME SHOOTING the gun. I suppose it's somewhat useful as a standard to make relative comparisons between guns, or loads, but that doesn't mean what happens in the rest will happen in my hands, or whether or not I can even notice it is happening.
Particularly with small amounts of difference.
Argue all you want, the math says (with ALL factors taken into account) one is slightly less than the other, or its not, depending on how the numbers work out. (GIGO)
Whether it makes any difference to the person shooting, or what gets shot, is a different matter, I think.
Argue all you want, the math says (with ALL factors taken into account) one is slightly less than the other, or its not, depending on how the numbers work out. (GIGO)
Whether it makes any difference to the person shooting, or what gets shot, is a different matter, I think.
Agree. And even then, what one person might be able to feel, another does not. The timer might tell a story that is humanly imperceptible.