After hours of tweaking the front derailleur, (toe in, toe out, up and down, screws loosened and tightened) shifting really sucks when going from the small ring to large. Just grinds against the large ring then goes over, no in between.

Could the chain or chainrings be a problem? Crankset is an old SR 48-34, chain is a new KMC Z33 NP Chain 5/6 Speed 1/2" x 3/32".

Shifting is fine from large to small ring and acceptable in the back 5 speed freewheel.