I tried it once many years ago when it first came out. The concept makes sense, keeping the powder near the primer end. It didn't cause any issues when I used it. It was so long ago I don't remember what cartridge.
I use it with 300 Blk subsonic loads. When filled to the top of the neck after a power throw it will compress enough to keep charge back by the primer. I have noticed a slight increase in velocity due to no air space in the case so work loads up to your max. One jar will last a life time.