ciener makes one that are realy good if your not looking for one hole groups. kimber sells one that used to be a ciener, but here recently they have started making there own. it should be good, but i haven't much about it. marvel makes to types. one the whole slides operates just like the 1911. the other the front of the slide is fixed and the rear operates like a browning buckmark. the seond marvel is the most accurate of any 22 conversions, but also the most expensive.