Sure, you can jump with it if you have been shooting with it the entire time. But if you want to change to it for a jump shot because you accidentally left yourself bad then no, you can't change to it. I too have answered this before.
I assume you mean that you stuck yourself and wanted to jump with this stick. I would say yes by wanting to use that cue for the sole purpose of performing a specialty shot, you are using it as a specialty cue and no you can't switch to it for the sole purpose of jumping with it. I have also addressed this before.
So what is a specialty cue according to you and what are they used for?
As you answer consider APA's definition:
A specialty cue is a cue that is optimized to perform one specific shot. A masse cue, for example - short, very heavy. Or a jump cue - 40" in length, with a phenolic tip. It has been optimized to perform one shot well.
As I mentioned earlier, let's say I have two identical cues. I use one to play with, and one to break with. Same exact cues. Would you let me use the one I break with to shoot a jump shot? Or would I need to use the exact same cue I'm shooting with? They're identical, remember. Same tip, ferrule, weight....everything.
Your rules are too ambiguous, and leave way too much to interpretation. Ruling that a specific ferrule type or tip type shouldn't be allowed? I've already shown you the definition from the APA regarding a regular shooting cue. If that "optimally configured" break cue of mine falls under 100% of the definition of a shooting cue, why do you feel the need to argue that my cue is a specialty cue? Can you tell me why my second cue ISN'T a shooting cue? I do shoot with it, occasionally. And people from my team have borrowed it when they didn't have their cue with them.
Tell me...why does the APA allow break cues? Is it because they're engineered to break better? Or to reduce exposing your playing cue to damage? That's the exact reason I use the "break cue" to shoot jump shots. Being honest, I could play the same shot with my playing cue. But seeing as the rules allow me a second cue, the rules allow me to switch between playing cues during a game, and my cue is a shooting cue, 100% compliant with the rulebook you're quoting, WHY CAN'T I USE IT? Argue away. Letter of the law says it's a legal cue. Deal with it.