I use RL-7 in my .221, works better than anything I've tried to date. Excellent accuracy, meters like water and a little goes along way.
I use RL-10x in three different .204 Rugers and its my first choice in that chambering.
RL-15 is a perfect mid range chambering powder although it doesn't meter that great it is very good in several guns I load for. I keep all three on hand all the time.
