Re: .223 hand loads.
Savage Model 10, .223 Rem. 9" twist, 22" barrel. Right handed rifle and shooter.
Have worked up loads for 55gr.& 60gr. Horn V-Max, 55gr & 60gr. Nosler Varmint, 55gr. & 65gr. Sierra BTHP, and 70gr. Speer SP.
Have used Varget, Rl15, Benchmark, H335, TAC, Win.748 powders. For me, Win748 was the least successful of all the powders. Lapua brass, CCI400 and CCI450 primers. Settled on Varget as the best powder for all these bullets in MY rifle. Settled on CCI400 primers for all loads.
Have tried all loads at "jumps" of .010", .015" and .020". At this writing, .015 SEEMS to be the best all around for all bullets. The "jump" distance still needs some minor tweeking.
The best accuracy for all bullets with most powders seems to be within the moderate to slightly nudging the max. recommended load.
The Sierra 55gr.BTHP seems the most accurate so-far. Have a few 100 yd, 5 shot groups in the .250" to .265" range with that bullet. The other bullets provide 100 yd, 5 shot groups in the 3/8" to 5/8" range when I am shooting well and weather conditions are favorable.
All shooting is done at an outdoor range from a not-too-stable shooting bench. My front rest is a Harris swivel bipod with legs out to the first notch. A swivel bipod is necessary because most shooting benches are not level side-to-side. When the bipod legs are fully "in" they have a slight springy effect which affects accuracy. The bipod is very stable when the legs are out to the first notch. A sandbag is the rear rest.
While at the range during load development I focus on breathing(don't wait too long after you are ready), sight picture(centered, full and steady), trigger control(pulling straight back), cheek weld (comfortably snug), grip on palm swell(comfortably snug), butt against right shoulder(comfortably snug), and left hand stabilizing the stock while leaning against/on the front of the rear sandbag.
All this works for me. It might/might not work for others.
Best wishes and good luck.