RE: .375 bullets
It may not be the absolute lightest, but that 200-grain weight is about as low as you can go and still be shooting a bullet instead of a round ball (just kidding). However, 200 grains is about as low as you can go and still have a practical weight in that large a bore size. The sd of this bullet is only .203 - even less than a 150 in .30 caliber.....