Manual for Noncommissioned Officers and Privates of Infantry of the Army of the United States, 1917 / To be used by Engineer companies (dismounted) and Coast Artillery companies for Infantry instruction and training

by United States. War Department

Section 6. Trigger squeeze.

Use the first joint of the fore finger to squeeze the trigger. It is the most sensitive and best controlled portion of the body. As you place the rifle to your shoulder squeeze the trigger so as to pull it back about one-eighth of an inch, thus taking up the safety portion, or slack, of the pull. Then contract the trigger finger gradually, slowly and steadily increasing the pressure on the trigger while the aim is being perfected. Continue the gradual increase of pressure so that when the aim has become exact the additional pressure required to release the point of the sear can be given almost insensibly and without causing any deflection of the rifle. Put absolutely all your mind and will power into holding the rifle steady and squeezing the trigger off without disturbing the aim. Practice squeezing the trigger in this way every time you have your rifle in your hand until you can surely and quickly do it without a suspicion of a jerk.

By practice the soldier becomes familiar with the trigger squeeze of his rifle, and knowing this, he is able to judge at any time, within limits, what additional pressure is required for its discharge. By constant repetition of this exercise he should be able finally to squeeze the trigger to a certain point beyond which the slightest movement will release the sear. Having squeezed the trigger to this point, the aim is corrected, and, when true, the additional pressure is applied and the discharge follows and the bullet flies true to the mark.