U/F~4 is usually used as combo filler for very high launchers, for Dragunov it's fairly useless as he has no launchers in which U/F~4 would be practical to use. Now I'm not referring to U/F~4 crossover at the wall either, which is possible but slightly lacklustre for Dragunov, I'm referring to using U/F~4 against a standing/guarding opponent to knock them down.
I'm unable to find any posts regarding the crossover recently, but it was originally from DR.
While the applications are limited, the crossover could potentially be a very strong tool for breaking turtles. If the opponent has a tendency to play defensively on +frame block attacks, such as iWR+2 and b+1+2, it may be worth trying to use it once or twice a game, or until the opponent is no longer complacent.
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The crossover only seems to work on short/small characters, therefore usually female characters
The list above is incomplete but should give you an idea of who the crossover works on.
Guaranteed combo - U/F~4, d+4, FC d/f+3
This sets up running oki post hit and iWR+2 seems to be the best option post combo as it will catch quickstand and forward roll, get blocked and +4 on side rolls, and can't be launched by wakeup 3. Unfortunately rolling away (back roll) will evade the running 2 and leave you open for punishment so it's no risk free.
N/A - No videos yet recorded.
Did more testing versus a good portion of the cast where the crossover might be possible. Did some testing on my old list and today had almost no luck with crossing over Alisa, so I've changed it to a "no".
Interesting enough was discovering how wonky Mokujin and Ganryu's hit boxes are. Mokujin seems to retain a set height, no matter what the height of the character, but can't actually be hit unless he's standing that tall. For instance I first randomly selected Moku-Dragunov and even while hunched over, being well shorter than Dragunov is, I was unable to jump over him. Similarly with Ganryu I was hitting an invisible wall when trying to perform the crossover, only thing I could think of is that Ganryu being a partial Jack clone retains a vertical collision box putting his height closer to Jack. As with Mokujin, his actual hit box doesn't extend past his visible height making U/F~4 unable to crossover or even hit Ganryu.