My son is seriously into archery, and even weighs his arrows like we weigh our powder & boolets. Well, here's the scale he uses, and it's ideal for reloading too. He got me one, it's been reliable so far, dead nuts on with known weights. Just a heads up, I've got no investment in the company. A nice convenient instrument at a reasonable price.

https://lastchancearchery.com/shop-1/pro-grain-scale