It would have the ability to use higher BC bullets for "long range" rimfire shoots.
That sounds like the most marketable reason. The number of target shooters compared to the number of hunters has been increasing for a while now.
Long range/precision/practical Rimfire matches are popular right now, so Winchester is probably seeing a market opportunity. Several reasons for the popularity are that rimfire matches don't take such an extensive shooting range as long range centerfire matches, so are able to be done in more locations, and it is also far cheaper to equip the shooter.
Only 22 Long Rifle ammo is legal in PRS matches (or any other sanctioned rimfire rifle matches I am aware of). Benchrest ,Silhouette, Bullseye you name it. Only 22LR is allowed.
THAT is not likely to change. If it were- 22 magnum and 17HMR would already be legal for those matches..
I really believe you are missing the point as to why Winchester is developing the 21 Sharps round.
Hint- it is NOT to compete against the 22 LR as match cartridge.
