EXCEPT WITH THE CORELOKT.........
Yes, the 170gr RN is designed to open up at .30/30 impact velocities. However, it will also stand up to .30/30 muzzle velocities as most of what gets shot with a .30/30 is at just over knife-fighting distances. (from my LE training, I KNOW that someone under 21', with a knife is an immediate threat!!!). Some of MY deer shot with a .30/30 have been that close......
The 170gr Corelokt will suprise you !!! Fired from a .30/06 at ~2,700fps, it'll be down to 2,250fps at 100yds, or about muzzle velocity for a .30/30. Published B.C. for it is 0.205 (My handloads run just a tad over 2,300 for .30/30)
I've had VERY good luck with the Speer 150FN at ~2850fps from the .30/06. The 170gr Corelokt may be just what you're looking for.
Only way to know is try them.
But I still say try the 180 PtSP-CoreLokts. They're very good, too!
And Yes, I know the Factory loads are still available, for over $25.00 a box....of 20! or about what it cost me to load 100 of them from my "stash".