That is incorrect...
Unique can be used with cast bullet loads utilizing jacketed bullets... most load data is available in Cast Bullet manuals..
Unique will equate to approximately 22 Win Mag speeds...
Max load listed with say a 54 grain cast bullet is a charge of 8 grains of Unique, giving an MV of 2200 or so fps.. with a pressure of < 40,000 CUP...
with a 41 grain cast bullet, 8 grains of Unique lists a max pressure of <36,000 CUP with an MV of 2444 fps..
Don't exceed and don't use filler... small rifle or small pistol primers either can be used... Rem 6 1/2 primers are perfect.
You can use cast bullet data for jacketed loads, as the pressures used in cast loads are FAR below what these cartridges are usually rated for...
most people who speak against doing this, have never tried it.. or they screwed up and condemn the entire concept...
or they know a friend, who has a friend, who has another friend, that screwed up...
8 grains per load, will give one 875 rounds out of a pound of powder...
a 40 grain bullet, and you have a round more than capable for 200 to 250 yd prairie dogs, which is about the distance 80% or more of them are taken..