Sounds like a worn synchro. 100K miles on the original synchros would be impressive. Heck, even half that, if the car was driven aggessively in its life would be impressive to me. It won't get better by itself. only worse.
The synchro does just that.. synchronizes two moving parts to make them mesh without noise. You could continue to wear out the syncro, or perhaps start "double de-clutching (shifting first to neutral, let out the clutch, then put in the clutch and shift to 2nd). Double de-clutching is how we used to do it in the "old days"
The "turning" could also be an indication of transmission or motor mounts that need replacing. As they wear, the alignment of these two components changes. Cornering forces make that alignment even worse.
Linear Mode
