In my Pacnor i use N120 mostly for sabots. H4198 has lower peak pressure for sabotless. You can get more velocity and lower pressures with H4198 sabotless vs N120.

N120 however produces some very good speed with sabots and 200gr bullets with very nice pressures.

Personally i think BH209 will really surprise you with a 300gr bullet in that 22" barrel. It should easily handle a recommended max load at around 2100fps.