H110 and 296 are "slow" among the pistol powders, but they are still in the upper third among all powders. Faster powders do well with lighter bullets, but as you move up in weight performance improves as you move down in burn rate. Heavier bullets take longer to get going and that allows more time for the "slower" powder to build momentum. Size matters, when it comes to barrel length, so best to try as many combinations as you can.