I only have one rod but use it through 222Rem, 6mm, 25-20, 6.5, 32-20, .360 up to 308W with no dramas - trick is to get the correct bore guide for your rifle action and have the chamber insert to match the cartridge and buy a decent quality (expensive) rod to start with. then make sure that you have a robust rest to cradle the rifle whilst you clean it. Never had any issue with rods flexing, but if a nylon coated rod is gong to damage your barrel then something is wrong somewhere...
Not wanting to promote any business in particular, but have bought all mine from Reloading Solutions. Don't recall the make of rod, Dewey(?) perhaps, but jags and brushes all readily available from RSD, Norman Clark, etc. (Norman is at all major meetings at Bisley and will bring stuff down if ordered in advance) - if you get the right size spear tipped jags you can then fine tune bore cleaning by choice of patch size etc.
Cheers.
P.S. agree with K about the distractive properties of the harmonic motion experiment...