Does Grip Size Matter?
While grip length does not really affect trigger reach distance, the circumference of the grip does. “Grip circumference” is the total distance around the grip, usually measured at its widest point. Some grips are wider at the top, bottom, or in the middle, while others maintain a relative consistent circumference for the entire length. (I remember the original grips on my S&W Model 19 revolver got wider towards the bottom and that was one of the reasons I replaced them with a set of Pachmayr “Gripper” grips. The new grips allowed my little finger to contribute to holding the gun, while with the original grips my little finger just got pushed to the side.) Some grips are more round in profile, while others are square; some are wider at the back than they are at the front.
Some experts say that the circumference of the grip needs to be narrow enough so that the side of your trigger finger does not rest on the grip. This is because as you press your trigger, the muscle in your finger tightens (and enlargers), and that can press against the side of your gun and potentially move the sights to the left (if you are a right-handed shooter). This is why some instructors told me my SIG M11-A1 was too big for me. However, I have not found this to be a problem, at least for me. (Perhaps any sideward “push” by this muscle in my finger is off-set with something else I am doing with my grip that counter-acts it.)
Optimally you will want your fingers to contact the grip on your pistol between the first and second joints of the lower fingers on your hand that can grasp the grip. This allows you to apply pressure to pull the front of the grip back towards the palm of your hand without apply any lateral (i.e., side-to-side) pressure with your shooting hand.
The proper grip circumference for your hand will enable you to more consistently control your pistol’s recoil and make trigger manipulation easier. Ideally you would want the middle finger of your hand to be able to reach around your pistol’s grip and contact your thumb.
There are often things that you can do to change the grip circumference. These include:
1. Putting a grip adapter, replaceable backstrap, or different grip panels on your gun to increase or decrease the circumference.
2. Having a “grip reduction” done to reduce the circumference. (But, this is usually limited to polymer-framed pistols.)