At longer ranges, bullet drop plays a significant role in targeting. The effect can be estimated from a chart, which may be memorized or taped to the rifle, although some scopes come with Bullet Drop Compensator (BDC) systems that only require the range be dialed in. These are tuned to both a specific class of rifle and specific ammunition. Every bullet type and load will have different ballistics. .308 Federal 175 grain (11.3 g) BTHP match shoots at . Zeroed at , a 16.2 MOA adjustment would have to be made to hit a target at . If the same bullet was shot with 168 grain (10.9 g), a 17.1 MOA adjustment would be necessary.