I'm confused as to why you wouldn't just, ya know, taper down on the suboxone. I mean, yeah, you can use basically any opiate to taper down from any other opiate. You could use dilaudid to taper off of fucking codeine if you really wanted. The question is as to how easy it's actually going to be to maintain any given taper schedule in regards to both dosage measure and timing, and whether the drug you're planning to taper with is really going to make it any easier than it would be just tapering with the drug you're already using.
There's a reason suboxone is usually the one that's used for tapering from things like oxy. It has a long half life, as a partial agonist it doesn't tend to get you terribly high so there's little temptation to eat through everything you have, it's fairly easy to measure doses and schedule it out...
So basically the answer is yeah, sure you can use oxy to taper from suboxone. It doesn't make a ton of difference, just decide what you want to use, carefully design a taper schedule, then stick to it. I still think that's a really absurd decision to make though, I feel the general consensus would be that oxy is much harder to taper with than suboxone, but hey, it's up to you...like, there's no chance that you maybe just want to do a bunch of oxy and are trying to convince yourself you want to use it to taper as a means of justifying it to yourself, right? I really just can't conceive of why someone with a regular supply of a drug so widely used to taper as suboxone and who was legitimately, 100% only interested in tapering off would think tapering with oxycontin would be a better option...
I almost forgot, bucci has a point. It's not that you won't feel a regular opiate for a few days after taking suboxone, it's that due to suboxone's high affinity for opiate receptors and the resulting blocking effect of suboxone, depending on your suboxone dose you're going to wind up having to take more oxy to get the same effect. But again, this is 100% dependent on your dose. For me I've gotten myself down to a relatively small dose of suboxone, maybe 1-3 mg a day taken in .5-1 mg doses, and I know I personally can use suboxone then go a few hours later and boot up some dope and barely suffer any blockage from the suboxone at all (one of the many, many advantages to maintaining a low-dose while on suboxone). On the other hand if you're on 8mg+ a day you may wind up having to either take a fairly large dose of oxy or wait for a while.
But again, that's what I mean about the whole switching over thing. It would be so much less complicated to just taper with the suboxone, but again, whatever, it's up to you.