I've tried these so far. Five shot groups, 50 yards, indoors, CZ 455
'Merican, five round magazines, rifle bag rested, used 2x7 Nikon Scope.

Groups:

CCI Mini Mag 40gr 1235 fps
Best: .50”

CCI Standard Velocity 40gr 1070 fps
Best: .31"

Gemtech Silencer SubSonic 42gr 1020 fps
Best: .45”

Eley Contact 42gr 1090 fps
Best: .21"

CCI AR Tactical 40gr 1200 fps
Best: .50"


My "go-to" ammo remains the CCI Standard Velocity. Not too expensive,
fairly available, subsonic. The Eley Contact has been hard to find and
is more spendy than the CCI SV.

The Mini Mags and the AR Tactical are damned close in specs.


Still need to get to the 100-yard outdoor range.


Your mileage will vary.