Not the powder mentioned in the post above but back to the dacron filler. The beauty of the dacron filler is the fact that it works so well in the bottle-necked cases, and the verious wads are dangerous in bottle-necked cases if they are below the neck into the shoulder area. That is a recipe for ringing. Straight cases less so. The dacorn will flow out of the bottle-necked case like air, but the wads that get on the primer side of the shoulder allow flash-over and the wad becomes a secondary projectile!

As others have said the most consistant loads in Bottle-necked cases where filler is needed is with Dacron fiber. The proper way to use dacron filler is powder on the primer,plus enough dacron filler on top of the powder charge so that when the bullet is seated the dacron column is slightly compressed,to avoid powder migration, no free airsapce in the case!

Caution NEVER place a solid wad down on top of a powder charge leaving airspace between the wad, and the bullet! That is a recipe for disaster!