Re: 6.5 creedmoor or 6.5x284
I don't own a 6.5x284 but I do shoot a strait 284 and a 6.5 creedmoor. I use the creedmoor for local matches and generally having fun shooting while burning less powder....my 284 is a 1:11" twist so I shoot 140 vld's at 2950 fps with 53 gr of N160, the creedmoor is a 1:8" twist so I shoot the 140 A-max at 2850 fps with 42.5 gr H4350....the higher BC is the 6.5 more than makes up for the 100fps difference.
If you do a 6.5x284 you should consider a long action to get the most performance, but then you already have a 7mag so I would recommend the creedmoor, it's a sweet round with low recoil and great accuracy designed for a short action. It should definitely fit well with your 7mag.
My creedmoor load stays above 1000ft # energy to 800 yds.......use your 7mag for the elk and the creed for everything smaller.