Subsonic - 220gr RN vs 240gr MK

[Murmur]

I've been using 240gr matchkings at subsonic velocitys on goats with OK success.
Place the bullet in the head or neck puts them down instantly but forget trying a shoulder shot - they don't even know thev'e been shot.
Question is would a 220gr RN bullet perform better on shoulder shots - would they even expand at all??
Has anyone tried a supersoft cast lead bullet with ultra large hollowpoint to initate expansion at these speeds???