I need to know more about this measurement. I am building a straight grip stock and need some info about this. Thanks in adavance for the help.

Drop at heel is the distance from line of sight to the rearmost upper tip of the stock. The easiest way to measure is to place the rifle upside down on a flat surface, resting on the front & rear sights. Then measure from that surface to the stock at the butt. That's your drop at heel.

Well there you go.I have always measured from centre of bore to heel. When designing the stock the centre of bore should be the top line of the stock through the barrel channel and it is easy to measure with or without the barrelled action being present. Length of face from under cheek bone to centre of eye has a bearing as does the length of neck and shape of shoulder and whether you mount a rifle with straight posture or crawl the stock.

Von Gruff.

its measured ccenter of bore to heel ... (as vg said) .. there is such think as negative drop

a straight stock is -1" or less, and is hard to use irons