I had the same Howa you are looking at, It was 2nd hand, it also loved 55gr sako game head and home load 50gr blitz kings. got on well with fox and crows with BK and Roe with game heads Never owned a 204 (friends have). I think it has been summed up well as the 223 being a good choice, Its easy to load for and ammo off the shelf is ........ I presume, still is easy to find.
Be confident the rifle is proven to shoot well.....Im sure it is but test it if you can if your not sure.
Oh and I posted the trigger unit to Mike Norris and it came back sweet as a nut with a lighter requested pull, Well worth doing
Good luck