sounds like you need a White Super 91 II but that's just a conical shooters dream rifle.

As for the 1-48 twist, I have actually had good luck with that twist and conicals although I am not sure ... maybe a 1-32 twist would be better. Its kind of an interesting question with the rifle you have and want to outfit. I guess I would look into what actually makes a barrel shoot conicals better then other barrels...