Such as the .3065" groove diameters used with 7.62 NATO M80 ball ammo's .3070" diameter bullets.That would not have been an example of a tight Palma bore. I had in mind the custom barrels like Krieger's .30 Tight series.
Always been fascinating to me that squeezing very uniform bullets down a few to several tenths makes them shoot most accurate. Upsetting them a few tenths bigger to greater groove diameters tends to unbalance them enough to make them shoot less accurate.