5. The shooter.
.22 rifles are inherently easy to shoot and after a shooter settles in with one can usually produce good groups.
My experience with microgroove barrels is they seem to wipe out cleaner after a similar amount of shots making me think the smaller rifling retains less residue and fouling than the wider spaced ballard rifling.
Interestingly my old Remington 572 likes the cheaper CCI minimag ammo over the greentag, it isn't microgroove of course, but it seems to shoot the cheap stuff better. I have been shooting this rifle since childhood and quite often so I would know...
I have never really seen a bad batch of .22 ammo.
A rifle like what it likes....
