OK... thanks for the input.   I hear you!
Not sure why I added the 400 yards part.  I was not thinking clearly late last night 

 ...   I have a 280AI and a 7 SAUM in the works for long range action and have no issues taking deer from 300 to 400 with that/those rifles in my field stand.
So back to the TCU and hunting in the woods and short ranges.  100 yards or less.
I want an accurate round that will drop deer at 100 yards or less that is 223 based and not kick like a 280AI or 7 SAUM.
What TCU caliber should I get or what other cartridge should I get, 223 bolt based, that will be the most accurate at 100 yards and drop a deer?
thanks haeffnkr