We can't tell any difference, whatsoever, between the 2 saws.
I checked out the 12" bars this morning. The groove in the Kobalt bar is obviously wider than the groove in the Dewalt bar. The .050 chain won't fit in the .043 groove. That makes perfect sense.
Both bars have the same A041 type mount. Both chains have 45 links. I laid the .043 chain on top of the .050 chain. Looked exactly the same length. Only differences I could tell was that the part of the chain that fits in the bar groove is narrower, & the cutters are smaller.
So, I put the Dewalt bar/chain on the Kobalt saw, & the Kobalt bar/chain on the Dewalt saw.
The Kobalt saw cut OK with the Dewalt bar/chain, & a little better than with the Kobalt bar & the current well used chain. But, TO MY SURPRISE, the Dewalt saw cut better/faster with the Kobalt bar/chain, than with the Dewalt bar/chain. Just to be sure, I put the Dewalt bar/chain back on the Dewalt saw & cut off another slice. Was noticeably slower.
Now I know that don't make any sense. And I'll do some more testing, when the new chains arrive. As of right now, I have to assume that as long as the saw has enuff power to turn the chain, the bigger cutters of the .050 chain just remove more wood, faster. Looking forward to doing more testing along these lines.
With the info I have now, I THINK I MAY end up running an .050 bar/chain on the Dewalt saw. I suppose the thin chain might be better if we were trying to cut bigger stuff. But the dull .050 chain buzzed right thru the 2" live limb I was cutting cookies off of. Not planning on cutting anything bigger than 4" with that saw. Most will probably be well under 3".
With all this in mind, I just ordered an Oregon 120DGEA041 bar. It should fit all 3 of our 12" saws, using the .050 gauge chain. Cheapest price I could find was just over $20, with tax.
https://www.ebay.com/i/184543236348?ul_noapp=true