I found the same thing regarding accuracy/velocity. I've found this to be true in the 3 different rifles/calibers that I have tried it in.23 will do great in your 243 also. I ran a 6slr with 105 Berger's at 3175fps for 1000 yd comp. That combo got me 2nd place 2 gun overall at my first world open match. 23 is very temp stable and gives really low sd/es. If you like rl22 you will like 23 better. I found rl26 gives more speed but 23 is always more accurate in my experience.
Shep