NEVER TRUST A MEC BAR

[William Davis]

It’s a volume measure dropping shot that varies in size and composition. Any loader same variance in drop weights are common, depending on how the shot packs and antimony content.

Ponsness Warren round drop bushings easy to open up in a lathe. Have a 3/4 & 7/8 bushing modified to drop the volume needed AA hulls shot & wad I use. Modified bushing drops are closer to 3/4 & 7/8 than factory. Mark them with a punch prick either side of the bushing # to indicate modified.

You can do the same to square MEC bars in the 4 jaw. Easiest method use a bar that drops heavy, lined with blue painters tape to desired. I use tape to check the hull-wad-shot fill before modifying . Measurement taped bushing gives a rough indication size needed to modify the 2nd bushing that’s too small. Best open in the lathe gradually sneaking up on the correct drops . In and out of the chuck several times.

I would bush out too large with tape before opening too small using less than precise machine methods. Over drill means use a new bar. Might consider keep using the taped one. Have taped bushings, volume pistol powder measure infrequently used, that lasted well, just check the drops before each loading session.

William

[Keith Doty]

I discovered years ago that most powder and shot bushings are approximate, the shot will vary quite a bit depending on size. I'm in the habit of actually weighing a set of 5 throws out of any bushings with the intended powder or shot charge before I use them. I have several I have chucked up on the lathe and "tuned" to get exactly what I want.

[edgarspencer]

I've stepped drilled several over the years, but the shot doesn't always fill in the upward direction, so the last two I did, I set them up in the Bridgeport and, using a boring head, bored them out straight thru, stepping out a few thous each time until they dropped what I wanted. Another method, which I considered, but haven't done, was to use an expanding reamer.