Seems it would work as good as the 300 blackout but a lot more bullets designed for that velocity envelope.
Use the 300 BLK mags
Should be about the same performance.
Similar to the 6.8-222 I have been thinking about. Seems Quality Cartridge makes brass for both.

That would be the 7mm MS necked to .277...call it the 27/270/6.8 MS...or whatever. Might just be a cool little booger...you could always rechamber to the larger cases if it didn't suit your taste.

Little brother to the BR series...or...??

~2500fs in the 7mm version with several powders, 26" bbl and a 140 gr bullet...not too shabby for such a little case...definitely something to think about for a limited range deer/antelope/varminting shooter...but the original 6.8 case isn't all that shabby either.

Be neat in a micro sized Single Shot or bolt receiver.

It's amazing what a change in bullet size nomenclature can do for a very old, very good caliber.

Better hurry up Boomy...someone else will get the jump on you for a "new" wildcat...

Luck

PS...I still have one more XP-100 receiver with the correct bolt head that's just bugg'n' the heck out of me to stick a barrel on...would be just right for a 6.8 sumpn-sumpn... Hahahahahahahaha

Luck