Does h110 and h335 both have the same burn rate? Are the powders of the same shape and size, is the case capacity of a 44 mag and a 223 the same? All this has an effect on pressure. Again load what u want, disregard publish data, but don't give advise for others do the same. Not only may u be sued if some were to be harmed, someone could lose their life...44 mag uses around 25 grains of h110 at max load, .223 uses around 25 grains of h335. Guess the small rifle still needs more charge to ignite the powder over the small magnum pistol huh?
Yes you should always work up loads when changing primers. Even if just changing brands.