My first saw was a ms250c easy to start an quick chain adjustment, it was a Christmas present years ago, mine worked great, was handy to make fast adjustments. Poor oil flow will cause a chain to stretch as well and some chains are just junk! I have a 2100cd that oils like crazy , well the oil cap was bad and it leaked out a bunch oil, when I fired it up I didn’t realize it was empty, and a brand new 36”chain sagged 1 inch, let it cool back down abt it was almost back to normal, oil is a big deal! lol I had to throw out a chain that was on my homelite 550, it oils great and the chain just keeps stretching, get it tight, make two cuts and it’s loose, it was a used Stihl chain so who knows the history.
But I like the quick adjuster on the 250, works just fine, but the oil hole hole in the bar needs to be clear to keep chain stretch at bay.