The length of pull (LOP) on a firearm is the distance from the middle of your trigger finger to the butt of your firearm’s stock. The beauty of a custom stock is that it can be made to your personal requirements. Most factory rifles come with a length of pull in the 13.5″-13.75″ range. You may want more or less, depending on your physique. Adjustable buttplates are available if adjustability is needed.
One common method for measuring LOP is to hold your arm at a 90 degree angle with your trigger finger straight up towards the sky. Measure from the point on your finger where you would pull the trigger (first bend/joint on your finger) to just inside your elbow. We recommend that you look online for a good video example of how this is done.