It depends. I made a shooting table top with "V's" for 3 rifles, it fits over my tailgate and locks into place. This is what I use when shooting on my range at home. If I'm using the range rod then my ram rod is laying on the table out of the stock. When shooting from the bag or hunting the ram rod is always in the rifle. So I end up shooting the same loads both with the rod in and with it out.
I don't know if one would consider this a test or not, but I have observed the results on several rifles. I have never seen indication either in POI or group size comparing one way with the other.
And I do a lot of shooting. I would say "Don't worry about it."