A curious observation:
I've been trying to find a high velocity .22LR round that works in my CZ455.
Over the last 2 years, I'd tried just about everything, with no real success - all grouped poorly to appallingly. The worst were CCI Velocitors, which were producing groups of 4 inches plus.
However, due to a serious error of judgement on my part at the beginning of this process, I had a whole slab of Velocitors (I fell for the marketing hype without really checking them in my gun first - very stupid). I felt I had to find a way to use these up.
So started playing with the set up. First step: remove moderator.
Miracle transformation: group size now around half an inch at 60 yards! Effectively single ragged hole a cm across (20 shots). I was astonished (and very pleased).
Anyone any ideas as to what's happening here, or had similar experiences?