Why would you want to take an eagle and try to make a chicken out of it...
Hey, why are you so critical of chickens?
Most people do the opposite--try to convert a chicken into an eagle.
The Swift is WAY better than an eagle--it's a peregrine falcon!
I have owned MANY Swifts and never had cause to complain about the factory standard twist of 1:14.
What action?
The Swift won't ever feed perfect out of a Remington. It'll feed but the semi rim makes it kinda grabby.
I'd stay with the 55 gr. bullets at high velocity - that's what a Swift is all about. Light recoil, super flat trajectory at normal hunting ranges and extreme disruption when the bullet gets there. There's nothing better for hitting small targets in the field at unmeasured ranges out to about 400 yards.
Yes, just not slick like an old M70. That's what I meant by "kinda grabby".