superdude

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    Brad Miller

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  1. GrumpyOne, I will only comment on the obvious. Wow. I simply provided the correct information because of your error in reading the plots. I fail to see how providing the correct information is a conspiracy of deception. Your conclusion is the exact opposite of reality. Readers beware. If you correct 57K’s mistakes, instead of apologizing for making an error, he goes on the attack by fabricating lies. 57K, lying destroys your credibility. You realize that, right?
  2. I don’t want readers to get the wrong impression of the results of that article based on your incorrect analysis. The results demonstrate that more gas contributes to more muzzle rise without a compensator (4-6 mm) and less muzzle rise with a compensator (4-5 mm) when pushing the same bullet to the same velocity with two different gunpowders that require different charge weights in both the 45 ACP and 38 Super. Side conclusion - a compensator works on the low pressure 45 ACP just like it does on the high pressure 38 Super. Barrel time has been used to account for differences in the point of impact of the bullet, generally comparing different bullet weights or different velocities. I’m not familiar with studies on barrel time and how far a gun moves during recoil with the same bullet weight at the same velocity. If you know of data on that, let me know.
  3. You can get an approximation of recoil force by using an on-line calculator, such as the one here: http://kwk.us/recoil.html You need the bullet weight and velocity. Enter any weight for the gun, just keep it constant. It also requires the weight of the gunpowder. Since you don't have that information, you can use a value of 0.1 (or 5 or something) for the program to work. Gunpowder weight does not add a huge amount of the recoil force to the 9mm, so it's not critical. Either way, the program will give you a recoil force estimate. The output value to look at is: energy ----- ft lb. And you might find this article of interest: http://www.shootingtimes.com/reloading/power-factor-recoil-bullet-weight-gives-edge/
  4. It is said that burn rate can be unclear where to rank specific powders when used in specific cartridges. The Ransom Rest does a good job of distinguishing between powders that require different weights for the same velocity. Powders that require more weight produce more movement. This is consistent with how the weight of the gunpowder contributes to recoil. More weight for the same velocity means more recoil, as your calculations have shown. The Ransom Rest's movement mirrors this. http://www.shootingtimes.com/ballistics/measure-relative-handgun-recoil/
  5. Ransom Rest movement can distinguish between different gunpowders even they they push the same bullet to the same velocity (same power factor).
  6. The recoil will be whatever it is. A fast powder (which requires a low charge weight) is the best way to reduce the recoil as much as possible while still achieving the required velocity. The only way you'll know what the recoil is, is to load some ammo and shoot it. Load some ammo, shoot it, and let us know how it goes. If it turns out to be too much recoil, your only option is to shoot minor. Recoil calculators that give different values for recoil are likely using different constants for the gas velocity; 4000 fps, 4700 fps, 1.25X, 1.5X, 1.75X. Not even the experts agree on which formula to use.
  7. Peak chamber pressure does not predict the gas pressure at the muzzle. http://www.shootingtimes.com/ballistics/compensators-pressure-gas/
  8. There are only two colors of true FMJ bullets that I am aware of, copper color which is gilding metal (95% copper 5% zinc) , and brass (~90% copper ~10% zinc) , like Montana Gold. Are you looking for polymer coated lead bullets? They come in a variety of colors.
  9. Point of interest . . . Hatcher discusses both the 4700 fps and the 1.25/1.5/1.75X factors (page 289 of Hatcher's Notebook) to calculate the effect of gas velocity contributing to recoil, and he uses both types (4700 and 1.75X) to estimate the recoil of a rifle round (page 290). Later in the text he uses the 1.75X factor for his rifle recoil calculations (value used on page 293), and the 1.5 factor for gas speed to calculate the recoil of a handgun (page 297). from Page 289: A Second Method The British Text Book Of Small Arms, 1919, states that "experiments of an extensive nature with ordinary guns" indicate that the average effective velocity of the powder gases may he taken as between one and two times the muzzle velocity of the bullet, with an average value of one and a half. The same work, edition of 1909. gives a value of 2 for the Short Lee-Enfield using cartridges loaded with cordite. In applying this approximation, a considerable degree of judgment will have to he used, as a figure approaching the higher limit must be used for very high pressure loads in short barrels, while low pressure loads such as used in shotguns and revolvers require a much lower figure. For rifles in the Krag class, a figure of 1.5 should be used, and this will work well with revolvers also, as well ss with shotguns having short barrels and using full loads. For shotguns having barrels of maximum length, a figure of 1.25 gives closer results. For guns such as the M 1903 Springfield or the Garand, a value of 1.75 should be used.
  10. Thanks, Guy.
  11. Load some ammo and try it. Then you can decide if it is too much recoil. If it is, try a 200 grain bullet.
  12. 165000/180 = 916 fps minimum. most folks will load to a higher power factor for a margin of error. 170 power factor: 170000/180 = 944.4 fps.
  13. Guy, does Hatcher explain how he came about the 4700 value? It seems that the speed of the escaping gas could be measured with some form of high speed photography. In any case, I suspect that there will be variation in gas speed, and that the quote "The effective velocity of the propellant gas, a much more difficult measurement, varies, in general, with the muzzle pressure and projectile velocity." will be right since muzzle pressure and projectile velocity varies. The gas speed is used as a constant, so as you say, the relative difference in recoil will be evident, and that's the question that is asked when comparing recoil between different bullet weights.
  14. There is disagreement about the value used for the escaping gas' velocity. SAAMI suggests using a multiplication factor of the bullet's velocity instead of the 4000/4700 values. http://www.saami.org/PubResources/GunRecoilFormulae.pdf "The effective velocity of the propellant gas, a much more difficult measurement, varies, in general, with the muzzle pressure and projectile velocity." High powered rifles x 1.75 Shotguns (average length) x 1.50 Shotguns (long barrel) x 1.25 Pistol & revolvers x 1.50 "The above velocity relationships were derived from extensive experiments by the British, published in "British Text Book of SmallArms" published in 1929 and confirmed by later work in this country."
  15. The 'square' or rectangle print on the primer is typical of all Glocks with all ammunition, even low pressure stuff. It matches the cut in the slide breech face. That's how people can tell ammo has been fired in a Glock. What power factor do you want your ammo to achieve? Minor or Major? If you want Major power factor, you'll need to increase the powder. You'll also want a chronograph to check bullet speed since that determines power factor.