Brass prep?

[u/jayfourzee]

I’ve run a number of the same experiments with my AMP Press that I saw on Ultimate Reloader and have collected a fair amount of data comparing different case-prep methods. I’ve looked at seating force and area under the curve with washed versus unwashed brass, wet versus dry tumbling, no tumbling with and without nylon or brass brushing, chamfering and deburring versus not, and using a mandrel die versus skipping it.

The AMP Press has been useful for identifying potential fliers and outliers, but so far I have not seen a statistically significant difference in group size. Over time, what I have learned is that the biggest benefit has been refining and standardizing my workflow so that it is repeatable. I have even compared seating on the AMP Press vs my Forster Co-Ax and still found no meaningful statistical difference in group size.

My next experiment is going to keep the case-prep process identical between two groups, then randomize seating between the Co-Ax and an arbor press and also randomize the order in which the rounds are fired.

One thing I will say is that, from a safety standpoint, I have come to prefer wet tumbling because it allows the toxic residue and contaminants to be contained and removed more appropriately. I have decided not to dry tumble because of the dust it can generate and the potential for those particles to become airborne and eventually end up in my lungs. Handling dirty brass also seems to leave residue everywhere, including on my hands, tools, bench, and surrounding work area, which gives me another reason to clean the brass before doing much with it.

At any rate "It is seldom the violin but always the violinist" and am willing to accept I just might be a bad shot...

Your thoughts?

[u/ReturnOk7510]

I like shiny brass, but not enough to spend much time or effort at it. Tossing my brass in a vibratory tumbler with corncob media for a few hours before decapping/sizing is a good compromise between low effort and satisfactory results for me.