No filler is needed. You’re putting the wad too far down into the Hull. When you seat the wad & shot, only push it pass the wad guide fingers on the press. You’ll hear an audible click when you pass the fingers. It’ll crimp perfectly after that. If you hold the finished shell up to the light, you’ll see that the base of the wad is seated just on your powder charge. When you crimp the shell, the crimp will seat the wad/shot in the perfect position. There is no need for a lot of wad pressure in these loadings. I’ve been doing this for years with fantastic results. Most of my 16 bore loads are 7/8 Oz too. 1 Oz will crimp even better.
I do this for the two types of wads I use for the 16. The SG16 (2.5” loads) and the DR (in 2 3/4” hulls).
