Welcome to the forum.
ES doesn't have much affect on accuracy at close range. Bullet weight variance will have more effect. The reason is that there is a kind of self-compensating effect at close range. A faster bullet is fired with greater recoil which causes faster muzzle rise, but it gets out of the muzzle in a shorter time frame, so it ends up clearing the muzzle with about the same muzzle elevation as it would have had with a lower charge. Try loading some rounds with 10% difference in charge weight and shoot some groups off bags with them at pistol target ranges to see how much difference it makes in your gun? Up to 25 yards, in particular, I think you'll be surprised how little difference there is. But try keeping the load constant and changing the bullet weight 10% and you will have a very different story.
To keep SD down for qualifying purposes over the match range officer's chronographs, several strategies may help:
Pick the right powder. Some are more position insensitive than others. You want a position insensitive powder. In .45 ACP, powders that fill the case well often are too slow to generate enough pressure to burn consistently, so don't expect case fill alone to be the determining factor. Your 700X may be doing this just fine for you. So might Bullseye. So might Hodgdon Universal. Spherical propellants like 231 (a.k.a., HP-38) or Accurate #2 will be easier to meter consistently and may do all you need as to position insensitivity? Accurate number 2, in particular, boasts of position insensitivity in its product description.
Consistent bullet pull helps, so use cases from the same lot with the same load history, and not mixed brass. Trim your cases to the same length so that crimping is uniform, even if that means trimming a little shorter than you are used to. Use a firm crimp.
Seat your primers fairly firmly, erring on the high side of firm. Primers do much better slightly over-seated than they do slightly under seated, insofar as ignition regularity goes. Use a primer with a cup that seats easily and with enough sensitivity for consistent ignition for the same reason. I like Federal 150's for this. 150M's (M is for "match", not magnum; Federal magnums are 155 and 155M) may be a little more consistent for you if all your other ducks are in a row.