Anyone have any favorite sub-sonic loads for the 223 Rem?

Read "17hmr Noise" Mines there

I do not have a SUB-SONIC load. Mine is for about 1850 fps.
5.6 grains of UNIQUE.

Accurate Arms list the following sub-sonic loads for the 223 Rem. Just wondering if anyone has tried them.

IMI 55 FMJ Solo 1250 powder 3.5 grains at 1139 fps

HDY 60 SP Solo 1250 powder 4.2 grains at 1111 fps

HDY 75 HPBT Solo 1250 powder 4.5 grains at 1052 fps

The first two are marginally subsonic and may give intermittent supersonic shots. That can make it sound like there's a huge difference from shot to shot when really the variation's pretty small.

I'm worried about loading high-speed rifle cartridges down to subsonic velocities with jacketed bullets. I'd rather use cast bullets, which are a lot less likely to get stuck.