I never load anywhere but the range, so I bet your problem is with the Chargemaster 1500. I started out with one.
I now use a Chargemaster Lite. In my opinion, it is a far superior unit than the original 1500 for outdoor loading. It is more compact, The wind guard actually works, the best I have seen. It has a built in level, and the charge tube is redesigned to avoid powder grains from just falling out. It throws plenty accurate for any shooting discipline.
I shoot thousands of rounds a year, every one loaded at the range, either in practice or a match. I haul the CM Lite everywhere. I keep a spare, but the one I use has been in service ever since RCBS came out with it.
One thing I do use is the actual power source that comes with the unit. I simply plug it into a small inverter from Best Buy, which is powered by a small motorcycle battery. This gives very consistent and clean voltage.
I think you are on the right track by learning to load at the range. It is by far the best option for finding what your barrel likes And for practice in general.
the single big draw back to loading at the range is you will catch yourself staying all day.