Well, you guessed it... CCI SV... 5/8" groups.
I assume green tag will do a bit better, it didn't when I shot 10 rounds the other day... then discovered my scope bases had worked loose...
5/8" groups
Norma Tac 22, BBM (meijer's), and GECO semi-auto are all the same bullet/brass (RWS brass), and shoot to the same POI/group size. 5/8 to 3/4
Aguila wasn't bad. 3/4
The various federal loads (510, suppressor, 810, etc) all seem to shoot around 1" at best (50 yards).
Mini mags usually do about 3/4 to 1"
CCI quiet are about 3".
Note: I shoot from the bed of my truck, sitting, rifle rested on a soft case on the bed rail. This isn't a proper bench, I'm not that great of a shooter... yada yada. They could all do better with a proper bench. Also, I'm a lefty shooting righty.
I have a vortex diamondback 2-7 on the rifle, on 7x for accuracy testing.
Typically with cci sv I can hit 12 and 20ga shells at 50 yards 10/10 times from this position.
ETA: FGMM easily does 1/2" when I do my part. I think off a proper rest I could shave 1/8" off all the group sizes, maybe 3/16" if I do it lefty and benched. This rifle is certainly limited by the ammo and shooter.