Beam scales have very high accuracy but not super great precision.
I checked my redding 5-0-5 scale against a very expensive digital one. Found that the high gain scale (5 to 440gr) was dead on all the way across.
But the low gain scale was off by 0.2gr across its 0 to 5gr range. So at 0 it's dead on, but by 2.5gr it's 0.1gr light, at 5gr it's 0.2gr light so 5gr on the 0-5gr scale is really 5.2gr. I discovered this may years ago when load developing for 45acp, if I worked up to 5gr on the low range scales and zeroed the low range switched over to one click on the high range I was off by 0.2gr, the same charge suddenly became 5.2gr when all I did was switch to the high range.
As far as accuracy goes it will drop charges accurate to one kernel of imr4350.
I load developed lots of my loads by then with out knowing so I just ignore it.
So the most a rifle load could be off by is 0.2gr which is nothing. Handgun loads could be off by up to 0.2gr could be something a 44mag load using H110 powder, 0.2gr is nothing, but say a 9mm loaded with nitro100nf that could be something. But working up loads properly you won't blow up.