My manuals show about 100 fps edge for the 6MM. I don't know if anyone makes a left hand model any more but I had one many years ago. Remington made the 788 in LH. I also had a LH 308 in the 788. I have had three each of the 6mm Rem and 243's. The first 6MM I had had the wrong twist and would only handle the round nose when it came to 100 grain bullets. Remington changed it but to late to compete with the 243 which would handle the longer bullets from the start. It hard to tell how the race would have gone had they both had the one in ten twist from the start.