Trajectory variation with different types of ammunition

Most hunters and shooters know that when you fire a bullet from any rifle, that there is a specific trajectory that the bullet follows, based on gravity and wind predominantly. However, most hunters don't go to the trouble to learn the trajectory for their rifle and ammunition. The trajectory of the bullet flight will vary considerably based on factors like barrel length, barrel twist, wind speed, caliber, bullet weight, and powder charge. There are other factors, but these are most prominent. Most important among these in terms of what you can directly control and alter, is your ammunition. This means that if you use one type of ammunition to sight in your rifle and another to hunt with, you most likely won't get the same bullet trajectory and might reduce your chances of getting an animal if your shot is beyond 150 yards. Many people sight in a rifle at 100 yards with a small bullet, like 140gr, and then buy a heavier bullet, like 180gr, for hunting a larger animal. The problem is that although there is little difference at 100 yards, the trajectory of a 140gr, and a 180gr bullet is very different beyond 150 yards. The powder charge will also vary from cartridge to cartridge depending on the manufacturer. My point here is that you should sight in your rifle with the specific ammunition that you plan to hunt with, find a trajectory chart for that ammunition, and fire your rifle at different ranges. See how your results compare to the given chart, and make notes. Once you have a validated trajectory chart, take that with you when you are hunting. If you change ammunition, repeat the process again. The chart below will give you an idea of how to compensate for wind, although it may vary slightly for your ammunition.  


I am in the process of building a new hunting rifle in .308 caliber, and I am planning to stock up on Silver Bear 140gr soft point ammunition, because of price and availability. This is the most reasonably priced hunting ammunition in .308 and has good reviews. If you are interested, there is a link below to the Silver Bear 140gr soft point ammunition page at ammunitiontogo.com. There is also a chart of the trajectory statistics for the Silver Bear 140gr soft point ammunition below. You should be able to find a similar chart for whatever type of ammunition that you are using.


http://www.ammunitiontogo.com/product_info.php/pName/100rds-308-silver-bear-140gr-soft-point-ammo/cName/308-762-nato-soft-point


Or try:


http://www.cheaperthandirt.com/ItemDetail.aspx?sku=AMM-690


-Richard