Twist rates were/are kinda established by the firearms mfg's but are not "written in stone" as being something that you and I have to stick with. These twist rates are recommendation's to fill the general public's need to shoot different weight bullets in the same rifle.
For instance, back in 1955, Winchester came out with the .243 and about the same time Remington came out with the 6mm. Win. brought theirs out with a 1-9 (maybe 1-10) twist while Rem. came out with a 1-12 twist. Shooters quickly found out that the .243 would stabilze both light varmint bullets and the heavier 95-100gn bullets, good for deer. The 6mm's 1-12 was only good for the lighter bullets and this error created just enough of a stall for the .243 to gain the shooting publics interest and kudo's. I imagine the 6mm's lighter rounds at slightly faster speed caused alot of deer sized game to "run off", also putting a strike against this round. Rem changed the barrels for the 6mm but the damage had been done.
This was all before my time and I have read it in magazines hundreds of times over the years but illistrates (to me at least) the importance of the right twist rate, especially on new cartridges being introduced to the shooting public. They (twist rates) can make or break a new cartridge.
A good source for twist rate "recommendations" is the bullet/barrel makers. Berger and Lilja immediately come to mind, but are not the only source. You can probably Googe "bullet twist rates" and get a ton of info on the subject. Compare a couple of different bullets from difference mfg's, say a .257 115gn Berger VLD and a Nosler 115gn Ballistic Tip. Look at the differences in overall lengths and bearing surfaces. The ogives are two different examples, the Berger being a "secant" ogive while the Nosler is a "tangent" ogive. Google that (ogive) too. Lots of interesting read.
Hope this clears up some of the confusion for ya. JohnnyK.