My Hornady GS1500 seems to lose calibration after a few weighings. I calibrate it every time I use it and just now I noticed it'll zero out... and then after maybe five rounds of loading 43.2 grains, I'll get a weight of 43.0. I'm using a Lee perfect powder measure so that seems normal to me. Well then I check the zero and it shows -.2 so I tare it and check the last charge and it reads 43.6. There's absolutely no consistency and I'm wondering if this is something I'm doing wrong or is it time to invest in a charge master. Last time at the range I had an ES of 46fps and noticed my groups starting to open up so I was leading to believe it was something in my hand loads. Any info would be great help. Thanks guys.