I did a few different 22 rimfire chronograph checks through my Marlin M60 stainless SB rifle. There were no attempts to check group size, just velocity on my ProChrono digital @ 10ft.
1-Aguila Super Max 30gr. 5 shots advertised Vel.=1750 fps
1563, 1550, 1455, 1483, 1433 Average-1496...