I'm gonna assume you're referring to an uprise on bars (as opposed to rings or p-bars), let me know if I'm wrong about that.
Anyway, I can 100% promise that the problem isn't with the uprise, but the tap swing. 95% chance it's with the swing itself, and 5% chance it's with your grip.
If you have strap bar access, do a bazillion tap swings there. Exaggerate the whip, make the bar bend with each swing. It can be helpful to practice swings with shoes or very light (say, 2.5 pounds or less) ankle weights, just to help you feel at whip through the bottom.
Then do a bazillion tap swings on the regular bar. Make sure you're keeping your wrists back when you swing forward, so you don't feel like you're peeling at the top of the back swing.
Your goal is for your hips and shoulders to get higher than the bar in the back of your basic tap swings. Once you get that height, turning a back swing into an uprise becomes pretty easy.
