Hi
Another story from my late FIL:
Sometime around 1943 he helped to test & evaluate the Bren Gun (Mk2 or mk3 perhaps?)
It was duly fixed firmly down on a special mount and a full mag was fired on auto at a target, either 100 or 200 yards, I can't remember which. When the target was examined to see what grouping was achieved they were surprised to see only one bullet hole, the rest appeared to have missed. Someone then commented that there was something strange about the hole, sort of slightly enlarged, it was then realised that all the bullets had gone through the same hole! When it was eventually returned it was recommended that a degree of imbalance be introduced to scatter the shot slightly, otherwise it would be wasted ammo.