Who shoots a Cooper rimfire, and how is the accuracy?
I am looking at a Jackson Hunter.
As mentioned Cooper's have a 1/4" accuracy guarantee and they will stand behind the guarantee. However the issue is not the rifle as often as it is the shooter. If one expects them to shoot to that level it requires good bench technique, wind flags, and some experience at shooting small groups, often it will require a search of different lots of match grade ammo to attain this level of accuracy.
Occasionally some of them will reach the 1/4" accuracy level with lesser grade ammo - mine for instance dotes on CCI Std Vel and Wolf Match, both inexpensive. If you are willing to settle for 1/2" groups practically any relatively good lesser ammo will work for that, I can shoot that size groups using Federal Eagle for instance.
In the end it is usually more about the shooter and conditions than it is about the capability of the rifle. Keep in mind that they are built to be a hunting rifle not a benchrest rifle, and with hunting rifle style stocks it can be extremely difficult to shoot good groups from a benchrest. There are more rifles capable of shooting 1/4" groups than there are shooters capable of shooting !/4" groups.
drover