I don't know what the twist rate on a Ruger is, but the standard for 6PPC is 1:13.5 or 1:14. That will stabilze up to about 87 gr. The PPC was originally designed to shoot 60-75 gr bullets. All the loading data (from load books) for the 6PPC that I have seen was developed with the old Sako brass, which is really weak brass. So, even the max loads are pretty weak. The 6PPC is currently the primary benchrest cartridge for 100-200 yard BR. I shoot a 6PPC in BR and myself and everyone I know uses Lapua 220 Russian brass that is fireformed in a 6PPC chamber. The 6PPC is nothing more than a 220 Russian case that has been fireformed in 6PPC chamber. Personally I cannot see having a 6PPC in anything that is not a pure benchrest rifle. If I wanted something like that in a sporter, the 6mm Remington Benchrest is a much better cartridge, and a much better long range varmit or light deer cartridge. A good well tuned 6PPC will regularly shoot .1-.2 in 10 shoot groups at 100yd and .2 10 shoot groups at 200. 3 shot groups really don't mean much of anything.