Hodgdon has data in both 44 Special and 44 Magnum for a 185 grain LRNFP. The weight is close enough that if you use their COL or longer, you will be just fine with it. They have it for Tightgroup and Trail Boss, which are among the light load powders I would probably consider. Actually, it's all pretty low level and the starting load of Titghtgroup for a 200 grain cast bullet in Lyman's Cast Bullet Handbook is higher than Hodgdon's maximum load by a good bit. Could be due to difference in seating depth, intended performance, etc. But down in the plinking or CAS load range there's a lot of variety. For that same bullet. Unique will be fine, too, and can probably be loaded at around 6-7 grains for a light plinker in the Magnum. For serious work, Lyman also loads it much higher.
