well the plan to get a lh 700 and rebarrel is a good one except for the cartridge you chose. the 700's in 17 fireball,221 fireball and 300 aac blackout all use a different bolt than the 223. the ejector is different because the short cases had problems, not counting the mag box diffences. in 17 rem it would work fine. not a whole lot out there for a left handed repeater.