The energies of all the bullets are sufficient to tumble, drop, and drift for a 10 mph crosswind are shown at m for the chicken and at m for the ram the least crosswind drift, even though it starts out with the lowest muzzle velocity. For this specialh also is the heaviest bullet , and we should try to launch it with the highest muzzle velocity that we can load safely.
This will assure that the crosswind sensitivity is minimized. Note that crosswind drift scales directly with crosswind velocity.
Thus, a 5 mph crosswind would cause half the drift shown in Tables 4. We will explain this in detail in a later section of this article. All these considerations illustrate the point that our bullet choice depends on our objectives, and our objectives certainly are different for hunting or target shooting. Our objectives also may be different for certain kinds of hunting or certain kinds of target matches.
It is not always best to choose the bullet with the highest ballistic coefficient to accomplish the purpose we have in mind. A question often arises about the effect of a small change in ballistic coefficient on a bullet trajectory. The question sometimes comes up because there may be a small uncertainty in the value of the ballistic coefficient of a bullet, and it is natural to ask how that uncertainty affects the bullet trajectory. A change in altitude or atmospheric conditions can cause such an uncertainty.
To gain some insight refer again to Table 4. For the low, medium, and high value of C. The table shows the values of remaining velocity and drop at the two ranges, and yds, for each case. It is generally surprising that a change in C , even a relatively large change like 10 percent, causes such relatively small changes in remaining velocity and drop.
The changes in these parameters are not in the same proportion as the change in C. A couple of general observations can be made from the table.
First, it can be seen that a change in C has a larger effect on remaining velocity at higher muzzle velocities than at lower ones. For example, when C equals.
This is a general trend in the data. The second observation is that a change in C has a larger effect on drop at lower muzzle velocities than at higher ones.
For example, when C is. This is also a general trend. Suppose that two bullets of different weight or different caliber have the same ballistic coefficient; how do the ballistics of the two bullets compare? To start with, assume that the two bullets are fired with the same muzzle velocity.
This gives a common basis for a generalized comparison. Consequently, if the two bullets start with equal muzzle velocities, at any range they will have equal velocities, equal times of flight, and equal drops. Unless they have equal weights, they will have different energies, however. Since energy is proportional to weight, the heavier bullet will have proportionately more energy at any range.
Usually the lighter bullet can be fired at a higher muzzle velocity than the heavier. The energy comparison cannot be generalized, however. The lighter bullet can catch up energy-wise with the heavier one if it can be driven at a high enough velocity to make up for the weight difference. Specific comparisons can be made after trajectories have been computed, and that is one of the uses of ballistics tables. Your wishlist is empty. Form Factor. Shot-to-shot Consistency.
Sources of BC Inconsistency. Variations in Bullet Dimensions. We appreciate your patience and continued support!
During this time of overwhelming demand, our team is doing everything possible to produce more bullets and ammo than ever before. What is a bullet BC? The two most common standards in use are: G1 for old, flat based, blunt nosed bullets G7 for modern, spitzer nosed, boat tailed bullets. Sign up for our reloading newsletter. What is a BC? The grain Power Point load in Winchester Magnum takes off at 3, fps.
Both are zeroed at yards and fired in a 10 mph crosswind. Those numbers might shock you. The puny little 6. But physics is physics. Pushing air out of the way sucks a lot of energy out of a bullet. The good news is that the W. BC matters more and more with distance. Choose your bullets based on things like accuracy and terminal performance. Certainly it will at yards, and beyond that it starts to become truly significant.
This is when you want to combine accuracy and terminal performance expansion with sleek shape.
0コメント