I use Hogdon titegroup all the time. 4.7 grains in a regular mag case. magnum primers 240 jhp . shooting out of a 6 inch 629 (it is my carry gun btw) and I load the same powder at 9 grains for magnum loads. I have NEVER had a problem. I can shoot the low special loads all day. I don't bother trying to find .44 special cases just load regular .44 mag works fine and No you do not need any kind of filler. the ONLY problem if you can call it that I have had is that I think it is kind of a dirty powder.