This technique alone will not accurately sight-in a rifle, but it may help get your rifle shooting much closer to the intended target than before.  Most rifle sighting is done first at 25 yards (22.9 m), then  at 100 yards (91.4 m). This will give you a more accurate sighting over long distances. A quick way to measure yardage is to grab a tape measure and see how many paces it take you to travel 30 feet (9.1 m). Do this a couple times and average the results. Once you know how many paces 30 feet (10 yards) is, you can measure out 25 yards (22.9 m). The process for this varies from firearm to firearm, but almost all bolt-action hunting rifles should be able to do this relatively easily. Make sure to place the bolt somewhere clean while bore-sighting. Move the rifle until the middle of the bull's-eye is lined up with the barrel. If you are not using a bolt-action rifle, you can insert a collimator, which is a bore-sighting instrument, into the end of the barrel to continue bore-sighting the rifle. Make absolutely sure to remove the collimator before firing your rifle. Check the scope to see if the crosshairs are also lined up with the bull's-eye. If they are not, adjust the settings on the scope in the opposite direction you want the scope to move, until the crosshairs go through the center of the bull's-eye. In other words, if you want the crosshairs to move up, you will have to turn the scope adjustment knob in the downward direction. Once you have finished bore-sighting the rifle, return the bolt to its original position.

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Write a summary of the previous text in Chinese:
在25码（约23米）外搭设一个有靶心的靶子。 取下步枪的螺栓。 瞄准靶心。 调整瞄准镜。 重新插入螺栓。