Careful on those... the ones that do usually include a big weight, nothing small like you'd need to verify a powder charge.crazy2medic wrote: ↑Fri Aug 07, 2020 3:40 pm Do scales usually coming with a calibration weight in order to verify accuracy, or are calibrated weights something I would need to buy in addition to the scale?
Electronic scales do! Balance beam scales not so much!
I always suggest buying a set of calibration weights in milligrams (because they are finer) so you can balance at the weight you need... for example I load a lot of 45acp at 4.0gr of Clays, so I calibrate my beam with 260 mg (which is 4.01 grains). And when I load 270 Win, I calibrate with 3700 mg (which is 57.1gr) and I'm loading between 56 and 59 grains.
Few scales will hold true across their entire range so it's always safest to calibrate close to your intended charge... if you calibrate with a 1 oz weight that comes with the scale, that's over 400 grains... if off by just 0.1% at the low end of the scale you could be a half a grain off which can hurt you in high end pistol charges, or leave you with a squib on the low end.
Several 9mm loads have a charge range of .3gr or .4gr from low to high so you can see where the variance could be ugly.