In fact these programs are probably more accurate in predicting changes between barrel lengths, as opposed to actual muzzle velocities. In actual practice both by myself and others, the data produced by both programs has proven to be an accurate predictor of velocities. Anyone interested in looking at all of the formulas and data may look up that article as well. To be able to use this program with the 50 BMG case I extrapolated some information for IMR 5010 powder. Bill Davis adapted Homer Powley’s slide rule type “Computer for Handloaders” into an equation workable with other applications.
Muzzle velocity of 50 bmg series#
The velocity calculations from these formulas apply only to IMR series powders. The second internal ballistics program I wrote was based on an article written by Bill Davis which appeared in the NRA book, Handloading. My own experience has shown it to be a reliable indicator, too. LeDuc’s contribution to internal ballistics has been found by a number of authorities to be quite accurate in predicting velocities, often within a few feet per second. Most recently there was some good coverage of it in the January/February, 1994 issue of HANDLOADER magazine. Some articles in other magazines have been published over the years about the equations. A Captain LeDuc developed this formula just prior to the turn of the century, based on the simple theory that as a bullet travels down a barrel, its velocity increases and the amount of pressure behind it decreases, both exponentially. The values for these two numbers in the accompaning chart are from this program.įor those not familiar with LeDuc’s equation, I’ll go into a little detail, but not enough to bore, I hope. His program also calculates muzzle pressure, and barrel time in milliseconds. One of them utilizes LeDuc’s equation and was provided by Bill Davis of Tioga Engineering. Specifically, how much of an increase could be expected with each additional inch of barrel? To answer this question, I used two different internal ballistics programs that predict velocity as a function of barrel length. Setting the negative aspects of longer barrels aside, I wondered how much velocity gain could be expected with longer barrels. Normally this would not be undesirable, but muzzle brakes become less effective with lower pressures. And as barrel length increases, muzzle pressures decrease. The presence of a muzzle brake has no effect on this recoil. This can lead to poorer accuracy, because it becomes more difficult to consistently shoot the rifle with greater recoil movement. Also, the amount the rifle recoils while the bullet is still in the barrel increases. In the #1, 1994 issue of VERY HIGH POWER we looked at how barrel stiffness decreases with length, and as a result potential accuracy possibly degrades too. There are a few drawbacks to choosing an extra long barrel, however. Adding barrel length is kind of like shifting a car into overdrive: more velocity for the same input. The other option is to use a longer barrel (having no effect on chamber pressure), utilizing more of the powder gases. One is to burn more powder, but exceeding safe pressures soon puts the brakes on that. With a given case and bullet, there are just two ways to increase The higher the velocity, the flatter the bullet will shoot, with less wind drift, more energy when it reaches the target, and an extended maximum range. This is especially true if that bullet also has a high ballistic coefficient. Barrel Lengths & Velocities for the 50 BMG Janu2:19 amīullet velocity is a very important ingredient of successful long-range shooting.
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