27 C.F.R. § 19.184 – Scale tank minimum graduations.

(a) The beams or dials on scale tanks used for tax determination must have minimum graduations not greater than the following:

(b) For scales having a capacity greater than 2,000 pounds, the minimum quantity which may be entered onto the weighing tank scale for gauging for tax determination will be the greater of:
1. (1) 1,000 times the minimum graduation of the scale, or
2. (2) 5 percent of the total capacity of the weighing tank scale.
(c) The weighing of lesser quantities for determination of tax may be authorized by the appropriate TTB officer where the beam of the scale is calibrated in 1/2 pound or 1 pound graduations and it is found by actual test that the scales are accurate at each graduation.
(d) Lots of spirits weighing 1,000 pounds or less shall be weighed on scales having 1/2 pound graduations.
(26 U.S.C. 5006, 5204, 5505)