The longer the bullet is, the faster it must spin to gyro stabilize it. That is why you have to spin a football when you throw it. The smaller 30's caliber conical bullets are generally longer in proportion than the 40+ calibers are, look at the difference in profile between a 45 Colt bullet and a 38 Special bullet.
Good question on the pistol barrel twist, as they tend to be faster rates, and perhaps velocity is the difference, a faster (rifle) bullet needs less spin? Typical Dixie Gun Works single shot pistols have 1:18 twist, but report the Italian 44 revolvers with rates like 1:60 (Walker) 1:32 (Army), or in a 36 caliber Navy 1:18. Uberti specs 44s at 1:18, but the Patterson at 1:56.
This is all over the map, so who knows what works best?
A roundball needs much less spin than a conical, and muzzleloading rifles generally have a fairly slow rate of twist, typical are 1:56 or 1:64, but as fast as 1:48. The TC rifles were made to use the longer, heavier thompson "Maxi-ball" bullet, and had the faster twist, 1:48, and were reportedly not as accurate with a roundball as more traditional bores, but I didn't see mine as less accurate.