While I do not load for the 270, several loading manuals I have list IMR 4831 as the most consistent powder. The 223 is another matter. I have had very good results from VIHT N-133, but I know that others have used H 322, H 335, Varget, BLC-2, W 748, IMR 4895 among others with good results. Every loading manual I have give different powders as "best" or list no results at all ( because there is no clear "best"). It depends the bullet being used, twist rate and the quirks of your rifle. I think I would try Varget for the heavier bullets (55+) and H 322 for lighter bullets(<55) with WW cases and REM 7 1/2 primers to start with. The 223 is very versatile and results will vary widely( that is why it difficult to give a clear, straight answer) You are going to get a lot of answers for the 223, it does well with a wide variety of powders and bullet combinations. When shooting in a Handy rifle keep the pressures low to medium and bullets seated to SAAMI OAL (can't reach the lands any way) for best over all results no matter which powder you decide to try.