I have used a lot of H-335 powder, virtually identical to 748, with good accuracy in the 223. My loads are very similair to what you state in the first example.

My top load is 26.5 grains with great accuracy. This is of course in my rifle which has an after market Shilen barrel on a Ruger #3 action. I'd start at about 23 grains and work up.

The remodelled Springfield is the best and most suitable all 'round rifle. - Seymour Griffin wink