Mostly I shoot Winchester .38 Special FMJ as the indoor range I typically go to doesn't allow magnums (sometimes I use .38+P).
They don't have sandbags there.
The groupings I get are usually around in the center of where I am shooting., They are about the size of the palm of my hand.
I've tried to get the groupings one on top of the otherish from about 5-7 yards to practice. Even that is difficult.
Next weekend I am taking it to an outdoor range that does have sandbags. I'll let y'all know how I do there.