"5Tom" What distance are these targets at....??
I realise the topic here is primer difference and you show there is a difference but if both your test bullets are 70gr then I think you are using the wrong powder. My thoughts are that AR2209 is too slow for this bullet weight and you are loosing a lot of velocity with this slow powder for the lighter bullets.
You might see a different result with each type of primer, that bullet weight with a faster powder and I think tighter groupings. Then still I would think that different primers would need their own load development as one might perform better with perhaps even 1.0gr less or more powder due to the different ignition factor of the primer.
I'm not going to go into it further here other than to say I have a range of loads to test for my own plus a friend's .243W using 70-80gr bullets and the first pick of powder will be AR2208, then Reloader 15, Winchester 760 and a trial of some Reloader 17 which I don't expect to perform well. All using CCI 200's as they were my pick of a few some time ago.
All I need to do is solve some medical problems so I can get outside and do some shooting before the snow turns up in this part of the country.