Seems long ago, most rifle twists were in the 48" range. The European guns were ever faster twisted until in England, they found dangerous beats could not be killed with light loads that shot best in the faster twists. Such quick twists are usually found to shoot well with lighter chargers than slower twists demand.
Rifling twists were slowed due to the demand for more power on big game - read :"The Sporting Rifle and it's Projectiles" by Lt. James Forsyth concerning these 36" to 48" twists and how they fared on large and on dangerous animals. He pushed for 1/4 turn in the length of the barrels which allowed much heavier loads delivering higher speeds which game better killing power as well as better long range accuracy.
Talk about deer - the Red Deer(stags) of Scotland - barely, if larger than a BIG Muley or Whitetail, (most pictures of them with the hunter show large NA deer size) dogs were used to bring wounded game to 'bag'. Forsyth wrote this was good as the fast twist, 40 to 60gr. charges were better at wounding game than killing it outright, whereas with slower twists and heavier charges, the round balls killed outright.
Today, ML barrels have slower twists. We know they shoot best at longer ranges- starting at 50yards and on out, if heavier charges are used. We also know there is enough of a difference in trajectory to make the heavier charges worthwhile, especially in the West where longer ranges are common and stalking closer cannot be done much of the time.
I test my rifles and work up the most accurate load for them - with water based lubes for target and with oil or grease based lubes for hunting. What I have found, bar none, is that with oil - there is one load that shoots the best & it is considered by many here to be too much powder - oh well, it is the most accurate and THAT is what I use. In my rifles, oil lubed patches require at least 10gr. MORE powder than water base lubed patches. If I am target shooting with an oil or grease patch, I MUST use the heavier charge, which means more points in score - it also means while hunting, the best accuracy, the flattest trajectory and the most killing power. To use less than the BEST load, is imoral and a tragedy perpetrated upon the game sought, imho.
Accuracy at 25yards, in the true meaning of accuracy means very little & can be achieved with squib loads that would barely kill a ground hog. Accuracy at 50yards starts to have a lot of meaning and accuracy at longer ranges where the game is shot, or scores are made are even more important. A rifle can shoot a tiny one hole 5-shot group, barely the side of 3 balls touching in a cloverleaf with a tiny charge of powder - that will shoot wildly at 50 yards and beyond. If you only shoot paper at 25 yards - and don't hunt, you can get buy with tiny charges.
Lewis and Clark found out quickly, the small bores and small loads of The East (late 1700's and early 1800's), did not far well against the elk and bears of the plains. Even the .54 calibre rifles they had, model 1803's it is said(and argued against), did not kill well. Those shot a 220gr. ball with 80gr. of powder in the issue load.
Benjanin- can you tell us where you found this tidbit of information?
"you think you need to shoot 100 grains or more for hunting deer, remember that the original longhunters frequently shot loads in the range of 35-40 grains and they hunted for a living"
Were these the men who actually shot deer, elk and buffalo to feed the forts? If so, I thought they were normally army and shot regulation charges: round ball, or buck and ball ctgs. both of which were for their .69 calibre muskets and charged with 165gr. of powder up until 1820 or so,and then 135gr. afterwards. The common .54 rifle charges were with patched balls and in the realm of 80gr.of rifle powder. I've never seen in print where these "market hunters" used less than the issue loads.