December 5th, 2014

Bench Hacks 101: Modified Straw Trick for ChargeMasters

RCBS Dispenser strawHere’s a clever, easy modification for your RCBS ChargeMaster electronic powder dispenser. Many folks use a McDonald’s straw to smooth kernel flow out of the dispensing tube. Forum member Mike S. (aka in2deep) found that, even with a straw in place, he sometimes got clumps, which dropped 5-6 kernels at once, throwing off his dispensed weight.

Mike looked at the situation and ingeniously decided to trim the straw into little v-shaped arms or prongs. This helps to break up the clumps, so the kernels flow out the end of the tube more consistently during the dispense cycle. Mike writes:

Soda Straw Modification
This is a further tweak of the popular soda straw modification as the original mod would still allow Varget powder to collect in the straw and dump sometimes as many as 6 or 8 or even more extra kernels in the pan. It would sometimes signal an overcharge, but even when it didn’t there could be as many as 6+ kernels too high or too low (total spread of 12+).

The little arms (prongs) on the straw tend to separate the kernels into groups of 1 or 2 or 3 and prevents piling and many times the throw is now within 1 or 2 kernels of the desired weight.

RCBS Dispenser straw

Straw Cutting Tips — Mike found the shape/angle of the “arms” is very important. If the cuts are too fine or too course it allows the kernels to collect almost like before but the illustrated angle seems to allow an average of only 2 or 3 kernels per trickle input from the machine. This means that more charges are much closer to the actual desired weight and max kernel variances will be cut in less than half and there will be almost no overthrows.

Credit Boyd Allen for sourcing this tip.

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