My nose sprockets on various saws used to seize up now and then and stop the chain moving.
Sometimes it took quite a bit of fiddling around to free things.
Then about 10 years ago I stopped oiling the sprocket bearings and since then there's been very few sprocket seizures.
As mentioned, most bars on my saws don't have oil holes at the nose end..
Actually I'm not sure exactly what nose sprockets do. They don't drive the chain and I can't see that they help to keep the drive links from falling out of the bar groove.
I'm not milling though, just cutting firewood
Thanks for you input mate. Il stop greasing my bar tip sprockets.. il keep using nose sprockets though.. cheers mate