Prone shooting needs a longer, higher healed stock - offhand needs a shorter stockm lower heal - that is why my Match rifle back in the 70's had an adjustable butt plate, both for height and for length. We don't have that luxury with muzzleloaders, so we comprimize - most people shoot well with 13 1/4" to 13 5/8" - the 13 5/8" being for long necked individuals.
Modern American rifle stocks having down slanting, super high Chinese pillows for cheek rests and a demand for low mounted are mostly to blame for stock crawler's habits today. These gun styles taught the young(boomers and younger) to crawl a stock to where if a stock isn't way too long for him or her, the shooters bloodies his nose with his thumb or cuts his eyebrow with the scope bell. Weatherby eye-brow - ever heard of it? See, it was Roy, himself who restricted most people's ability to shoot well offhand today. I see people shooting rifles with stocks way too long and their right shoulder is way back on an angle behind their shoulder blade, rifle butt way out on the arm when shooting offhand and thinking that's correct. NOT. The gun should be brought to the shouder/arm joint for pointy butts, tucked into the shoulder pocket with flat butts, with the head high while looking (addressing) the target. The head is not scrunched down over the comb and shoved forward. That stock crawling tilts the eyes too much, which puts your equilibrium out - your body then fights for balance rather than letting all your concentration fixate on the sights and target alignment. The eyes should be as horizontal with the world as possible to maintain ballance. Watch an Olympic Shooter's stance - straight up and down, head held high, gun brought to his head, not head down onto a stock. Comb heigh, heal height, toe height, sight height - all are important - best to try a lot of different guns of different patterns. Some require a bit nor drop and/or length - while others require just the reverse.
What all this diatribe is for, is to show that a heads-up attitude allows a shorter stock than many people have come to believe what is right for them. It is also the position ACCURACY shooters adopt - ie: Olympic Offhand shooters - watch 'em. Perhaps the long stock syndrome is due to shooting an adult's gun when young and mostly off the bench, I don't know. I do know that many people will shoot better if they shoot with shorter stocks and learn to pull their right shoulder forward, stand erect, address the target, then place the butt into the pocket- either on the pec muscle for flat butts, or into the pocket of the shoulder/arm for hooks. Standing thusly, not only improves offhand shooting, but also allows recoil to push the shoulder back, obsorbing recoil which also shoves the shoulder downward as it's attached to your body, and then pulls the comb down off the cheek, reducing or eliminating cheek bashing. If the stock is too long, the arm is already at it's rear travel and the gun cannot recoil back and down, so the result is an upwards smack to the cheek. Stocks with to little drop at the comb are really bad for this.
in my opinion, of course