The following information on drawing a handgun from a pocket comes from Section 54 of Shooting by J. Henry FitzGerald. Shooting is also available to purchase in print.
The outside overcoat is one of the very best places to carry a small revolver. An officer may walk along with his hand in his pocket and no one on the street would know that he had a revolver in his hand—this, of course, if he felt he might have occasion to use it. Some police departments object to the officer placing his hands in his pockets, but the usual time when this would be necessary would be at night in dark, unfrequented streets.
As an officer acquires the art of handling his revolver properly he will be able to scent trouble and as certain conditions appear to him he will prepare himself for quick action, which means in extreme cases the quick, accurate use of his revolver. How many officers have lost their lives because they were not prepared,—an unlocked door, the officer investigating without first taking all necessary precautions. First, if necessary, call help. Both sides of the building should be watched. Next, draw your revolver and enter building carefully, first noiselessly swinging door open slowly, forcing it back until it rests against the wall. This is to convince yourself that no one is behind it when you enter. Try to enter without casting a shadow of your body into the building. Wait in the shadow until your eyes have become accustomed to the inside darkness, otherwise you will only notify the intruder of your presence. It is not an act of bravery to walk headlong into danger unprepared.
In a small city where I had previously given firearm instruction to the police an officer came to me and said: “You remember on your last visit you told us about carrying a revolver in the outside overcoat pocket?” I told him I did. “Well, that instruction saved my life. I was standing on the corner late one night when a man crossed the street and came toward me. It was cold and I had my hands in my pockets, my revolver under my right hand, when about ten feet away he stopped and drawing a revolver fired at me. I felt the blow of the bullet but fired my own revolver before he could fire the second shot and I stopped him.” The bullet fired by the officer’s assailant struck and imbedded itself in his heavy hunting-case watch which I was shown. The officer had a miraculous escape from the first bullet, but his speed of getting into action and the accuracy of his first shot saved his life. This could not have been possible with a revolver carried under several coats and in either hip pocket or holster. We rarely need a revolver to protect our lives, but when we do need it we need it badly.
A leather pocket built in the police coat would be a good place to carry the light model revolvers and the front trousers pockets are also much used for carrying small revolvers by plain clothes men, always remembering to place thumb over the hammer when drawing the arm to avoid catching in the cloth. It is not claimed that the pocket draw is faster than the properly carried holster, but it is fast enough to beat the inexperienced or those who persist in carrying their arms in the hip pocket.