It is highly unlikely that the exact number of grams needed
for each sample can be obtained using a riffle while adhering to the
requirements of Table 1. Do not add or delete particles without using a
riffle in order to obtain the exact desired mass. The user must exercise
judgment to assess when the riffled mass is sufficiently close to the desired
mass so as to not materially affect the results of the test(s) for which the
composite sample is being prepared.