I have used several different RL powders in several different calibers and I do not have a gun that will shot the best group with RL powder. I have had groups with RL powder in about all my guns that would be plenty good enough to hunt with but I can use another powder and shrink the group just a little more. I use Federal 210 primers in my large riffle and Federal 215 primers in my magnum rifles. Would a different primer work better with RL powder.
I am not saying anything bad about RL powder I just can't find the right combination. I know that it is good powder because too many people are using it. It is talked about on this forum about being several peoples favorite powder. I have tried it in 243 Win, 6mm Rem, 270 Win, 7mm Rem, and 7mm STW. I have tried RL19, and RL22 in these calibers. If you are shooting your best group with one of these calibers and RL powder what primer are you using?