Just from what I have read, it seems like you would need a new barrel, but wouldnt need a new rifle. Although, as we are in Ireland, thats pretty much the same thing! New calibre, so you would need a licence for the different barrel. Would be interested to see how this progresses.

https://youtu.be/RpbyP7K5jHA?si=Xm5CnXi7wShX0zek

Not for me. I hope it never takes off. I have a cz 452 silhouette that prints tiny groups with most 40 gr bullets and from what I see on YouTube the groups from the 21 look great a 25 yards but useless further out. I also have a 17 hmr that can do everything that sharp can do . I think their trying to reinvent the wheel. I could never get rid of my 452 . They be better served putting their time and money in to eco friendly 22 lr ammo. Just my opinion.