I shoot a lot of 22 Hornet in the "other" preminum sporter rifle, the Kimber of Oregon.

I think my experiences would apply to a Cooper as well.
The most popular powders seem to be IMR 4227 and Hogdon Lil' Gun (LG), with the latter having the bragging rights for making max velocities without creating pressure problems. Load weights for LG usually range from 11 gr. to 12.5 gr, depending on your gun and target demands. A "reduced" load I prefer is 8 gr. of IMR SR 4759 with a 40 gr. bullet.
Bullets: Most makers have a "hornet" style bullet, a semi-point soft nose. I guess this is the style that helps accommodate most magazines. Personally, I prefer a spire point and I feed my KoO as a single shot.
Primers: There are two schools of thought on primers. Some of us prefer the "small rifle" primers; others prefer the "small pistol" version.
If you're looking for fun, the Hornet is a good place to find it. The Cooper will help.
