A powder meter tube includes a metering tube and a metering assembly. The metering assembly is retained in the metering tube. The metering tube includes a nut cutout and a graduated slot. The metering assembly includes a threaded shaft, a micrometer nut, a piston and a bearing. A threaded hole is formed through the micrometer nut to threadably receive the threaded shaft. The bearing includes a base and two spring fingers that extend from the base. The piston is pressed on to one end of the threaded shaft and the bearing pressed on to an opposite end of the threaded shaft. The spring fingers allow the metering assembly to be inserted into the metering tube and the micrometer nut to protrude through the nut cutout. In use, the micrometer nut is rotated in either direction to increase or decrease the powder capacity in the metering tube.