i suggest the following:
Remington nickel-plated cases, Remington 7 1/2 BR primers, BL(c)-2 or WC-846 bulk powder, and Hornady 50 gr' spire points. Work up your loads with either powder per the instructions on the container or the Hodgdon website.
the nickel'd cases should help with extraction; but so too does degreasing and polishing the chamber if you don't have one that is thoroughly clean and dry, and reasonably smooth.
my .223 Handi's both love Hornady bullets, but the heavy barrel'd one handles the 60 gr' spire points better from what i can tell. naturally, every rifle is a law unto itself!
i recommend you don't worry too much about velocity because you can get taller rings to get a 'flatter' shooting setup.....if you understand that...
it really does work, if it isn't a problem for you to use taller rings. i like 'em. it allows you to flatten your trajectory with a somewhat milder load, all else being equal.
take care,
ss'