If your collection of .22 molds don't pan out, try rounding up a Lyman 225107 mold. It casts a stubby little 37 grain bullet that worked for me in the past when dealing with slow twist .22 CF's. I had a Sedgley-converted Low Wall Winder musket that they in their infinite wisdom rechambered from .22 short to .22WCF. Talk about a slow twist! The little 225107 solved the accuracy problem.

(If you go that route be forewarned that it was a tough little bugger to cast, for some reason more so than other .22 cast bullets which often are an exercise in frustration.)