Not in my case. I had similar results with my 243. I've done a lot of load development with both those cartridges. For the 1st 8 or 9 lots of each, I was using CCI 200's exclusively thinking that they'd be more consistent than the Rems. It wasn't until I ran low on the CCI's & started replicating loads with the Rems that I noticed the differences. All my testing is done with 8x5 shot groups with every shot over a chronograph & the groups recorded with range buddy so the results are statistically significant IMO.
Over the last 6 months or so, I've been using GRT to find the OBT velocity & adjust the initial charge weight & initial pressure to match. It was with 2 identical 308 loads with the exception of the primer when I noticed a significant reduction in group size & had to adjust the charges to match velocities. The velocity difference was about 80 ft/s with the Rem 9 1/2's the higher velocity.
The Rem's also match the initial load entered into GRT expected velocities much closer than with the CCI's.
Since then, I've been replicating some of my previous 308 & 243 loads using the Rem's with improved results with every load so far.
I think the Rem's are under-rated.