I thought my lop was correct for my merkel .470 as it was my normal length for the bolt actions I have used. However, an experienced double smith looked at my tall build, chest size, etc and added an extra 3/4 inch by way of a kick easee pad ---- what a difference! basically it made the rifle more accurate from the first shot. I know that sounds a little silly, but the shots now all went to center after playing with loads and fill for a year. Now that I am more confident, well, it just gets better shot after shot. But with those first few shots after the lengthening, I had no basis for the confidence -- but it really helped both in accuracy and comfort. It seems too long at first, but now I know the difference between a well fitting double rifle and bolt rifle. I do envy those who can do a completely bespoke custom stock - it must feel excellent.