As a Machinist, I use dial calipers a LOT. I also reload and have a "Lyman" stainless steel caliper just for that. Calipers are perfect for reloading issues. I certainly DON'T use them for grinding a crankshaft or honing a cylinder bore when accurate readings to .0001" (a tenth of a thousandth) are required.
Of the dozens of dial calipers I've used (and it doesn't matter if Starrett or something Chinese), I often re-check my zero, as it seems as they wear, the needle will loose it's press fit on the pinion shaft and move slightly when the caliper is opened and closed quickly. In a low stress environment like reloading slowly opening and closing the jaws is more doable
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I also like using the case gages for checking re-loads before boxing them, however, they only check case sizing NOT COAL. Recently came across these my employer got in a box of supplies he bought from an estate;
https://www.topbrass-inc.com/collect...12832996851765
You get instant feedback regarding min/max SAMMI Specs for a caliber.