The biggest effect I've seen on it is more associated with changes in humidity. I check mine before each use and as long as the humidity hasn't changed much, the charge weight hasn't either. Mine does not leak, however I run a powder check and its a bit messy, If it pulls one flake of powder out with it once every 5 or 6 casings...... well, it adds up to a mess after several hundred rounds. All in all, I like it!