I'm wondering, is Appleseed contemplating the usage of the new 21 Sharp at 25M events?
What about at a Rimfire Known Distance?
Great question. At this time, we don't know if the 21 Sharp will have some of the safety concerns as some early 17 HMR rifles had when they first came out. So, I don't want to say definitively yes or no. Assuming there are no unforeseen issues, the answer would be yes, you can shoot it at a Project Appleseed event. To patch at a Rimfire KD you must shoot 22LR.
From what I have seen on YT it probably won't do very well accuracy wise. I doubt that changes until someone other than Winchester makes ammo for it.