Re: In need of new powder measure
A Redding 3BR is within your budget and can throw charges as accurately as you're looking for. I've taken data across a wide range of powders including IMR4046, IMR4895, H4895, etc. and the three sigma error came out to be 0.28gr, 0.19gr, and 0.18gr, respectively, for an <span style="text-decoration: line-through">80gr</span> <span style="font-style: italic">80% micrometer full</span> charge. IMR3031 came in at 0.21gr, for example.
The measure was mounted to the edge of a 1x6 poplar board using the bracket it comes with, the board was c-clamped to the edge of a heavy desk, and the lever was bumped slightly at the bottom of the swing where the micrometer cavity loads. It also has a Sinclair adaptor and bottle attached instead of the stock reservoir and baffle but I don't think it matters.
The measure is accurate enough to develop a linear regression from the data across several charge values so it can be entered into a programmable calculator, or excel spreadsheet, in order to get the micrometer setting for a given input charge weight, as well as the likely three sigma error (which tends to increase with throw weight according to the data(. This looks to hold true across a total of seventeen powders measured.
I still weigh every thrown charge and any flier comes from an error in technique like bumping the lever too hard or too many times although some bridging occurs from time to time but i don't have an explanation for that yet.
Cleaning the drum and mircrometer cavity helps but doesn't eliminate it entirely, thus the bump applied at the bottom of the travel. With some of the longer extruded powders it seems that double bumping or bumping at the top and the bottom of the travel helps reduce bridging the most but that's just anecdotal. And it likely over-compacts the charge but by how much I've not measured.
HTH, Pete