I recently came into ownership of a Remington 40X in 243. A very nice looking rifle with a stainless barrel; it doesn't need anything and could remain as is. But there is a Problem is, it has a 10 twist and the range of bullets that will stabilize is short. I was wondering if I converted it to one of the short magnums like the 300 S win. How close would it come to being practical as an ELR rifle?