Red Dot. From 2 grains in .32acp or .32sw long to 13 grains in .444mar
There is a whole litany of calibers that work very well in the 3, 4.6 to 6.5 ranges.
If you want to stay below speed of sound that is easy also. If you want to push up into the 1600 to 1800 fps just work off the higher side.
What's more a pound of 7000 grains of Red Dot will last you forever in the 3-4 grain range. Darn thrifty. Primers maybe pricey.