I usually have the powder charger (measure) attached to the horn's strap do it is always within reach. Too, if attached at it's base,
it is always pointing down and will not collect rain or snow.
Most of these are made from ctg. cases with the extractor grooves and rims turned off % with screw eyes soldered into the flash holes.
The larger ones of 125gr., 140gr. measures (top row right side) are made from brass tubing bought at a hobby store, with .015" wall. I used wooden plugs in the end
with a drilled hole across through the wooden plug, with thong/string through the hole. The plug is also glued in with CA.
A powder scale was used to weighting what each measure 'throws' so they could be marked.
LeValleyTools sells a phone-sized digital scale that measures in grains, grams, tare, etc, for $20.00, in case you do not have a powder scale.