I only recently heard about this shooting sport, which is now about a dozen years old. There is a Web site, and much more active Facebook page.
The idea is to essentially duplicate the BPCR silhouette shooting experience, but using traditional buffalo-era rifles either with dedicated barrels or with the fine removable liner barrels in .22 LR made by Crossno and Shaver. The chicken, pig, turkey and ram targets are scaled down proportionally, and shot at 50, 100, 150 and 200 meters.
Seems a lot of folks who dearly love their buffalo rifles are having a lot of fun with this game because they don't have to deal with bullet casting, handloading, recoil and cleanup demanded by the centerfire cartridges. And it can be shot on many ranges that only go out to 200 yards or meters.

http://www.22bpcra.com/

Yep, and if you use one of the .22 insert barrels, you can shoot your centerfire gun for both.