Don, I've done the same banana thing twice as an experiment, in a 2506 and a 204.
It matters, quite a lot. Something like a 50 percent reduction in group size, or more. I was amazed and horrified.
Bananas in their own group was like double or more the groups of the good, straight brass.
A small chamber moderates the effect somewhat, but blowing out and fireforming on centerline is a surprising big deal.
Now, I just glance at fired cases and if I have any doubt, I'll roll them on a leveled mirror. If I can see a wobble, it's gone. At two bits and counting per shot these days, I want to hit stuff.
