050 vs 063
I did a test where I did 10 total cuts in different wood with 28" bars (stihl 28" 050 & 063, tsumura 28" 050 & 063, & cannon 28" 050 & 063.) on a 660 running full oiler.
I then put all the bars in a vise and looked at the oil saturation in the bar grooves. There was a nice difference between how dry and wet the 050 and 063 are. ie. 063 bars were more saturated/wet in wood chip pack in the groove.
So does 063 oil better from 28" and up ? I believe it does.
Is 063 stronger? In some brand chains I believe it is. In stihl 050 chains, it's 063 up top, bottom half of the Drive links are swagged down to .050.
that said - I think it's far easier for the bottoms of 050 drive links to get dinged up vs .063. - from the chain coming out of the groove from needing to be re tensioned, or a long bar sideways cut or whatever. I have 30+ bars at the moment and all my testing I'll say that the only chains I've had an issue with the drive links getting dinged up are .050.
not so important - having/testing so many bars i'm constantly changing things around. I will say that mounting a .063 chain is far easier. Especially when the saw isn't on a table in the ideal setup. Doesn't really apply, but worth mentioning I guess.
lastly - 063 may not be on the shelf much where I am, but I can order 063 RS all i want. And at this point I think that's the best chain stihl makes. Square ground doesn't stay sharp. Rapid Micro isn't good in the long bar. Full skips seem to dull faster. Now if Stihl would make a rapid super half skip...that would be the ticket.