MEC Bushing Inconsistency

[magshooter]

Hello, I new to loading shot shells but not new to reloading. This is my first time using a bushing style powder drop as I have always loaded on a Dillon. I am loading on a MEC 600 Jr I am am finding what I think are big inconsistencies with my powder drop, ranging 2.7 grains apart. I am using International powder and a #32 bushing which says it drop 21 grains of powder. I understand that the MEC bushing guide is an approximate and it will not drop exactly 21 grains however I have gotten powder drops ranging from 22.2 gr to 19.5 gr. Is this normal fluctuation? Am I doing something wrong? How can I make this more consistent?

 

[MEHavey]

1-2 tenths either way is the MAX I experience.
FWIW: The way I determine the charge drop is to

1. Weigh a fired case, and ZERO the scale with case on it
2. Pull the shot bottle off
3. Drop a charge into the case weighed in #1 above, and weigh it again (net weight is now the powder charge)
4. Dump the powder back in the powder bottle (TAP the hull to get ALL the powder out)
5. Cycle the Charge bar (no shot bottle)
6. Repeat #3, #4, and #5 four more times for a total of five charge measures

Whad'cha get ?

 

[cfullgraf]

When setting up my MEC 600jr for a reloading run, I'd fill the powder measure and run about 20 or so charges through it before measuring the charges. The charge weight differences should settle down.

Try to operate the charge bar the same each stroke.

Load the shot bottle last, just before starting to actually load shells.

I always had at least the bushing above and below the one that the chart stated was the size for the charge I was looking for.

Over time and loading all four gauges, I've ended up with just about all the bushings except for several of the largest.

 

[kudu]

I try never to let my powder bottle get less than half empty and try to consistently have the same feel or motions when the powder drops. If you bump the press harder at one station the powder might compress more. After running for a period of time most powder drops are usually within 2-3 tenths of grains on my MECs. Now that would be horrible on a rifle/pistol cartridge, when I load rifle for accuracy it's got to be right on, shotgun seems to be 'good enough' and I have loaded several hundred thousand shotshells over the years.

 

[magshooter]

When I was measuring the powder I was measuring with the shot bottle on the press and would drop the shot each time after I weighed my powder and then go again and start with dropping the powder, then weigh it, drop shot. empty shot, then repeat. I did this because I was trying to mimic the way that it would actually be working when I began to load. I did after I made the original post switch out the bushing to #30 same international powder to see if perhaps it was just the #32 bushing that I was using before that was giving me the issue. However I still got a fluctuation over my first 15 powder drops I ranged from 17.6 gr - 19.3 gr. That is way to much of a variation and I am still stumped on why this is happening. The busing should only be able to hold so much powder so I am not sure how it is going almost 2 grains of fluctuation. It is a brand new press too I just took it out of the box 2 days ago and set it up. I only have the 3 bushings (29,30,32) that they give you when you buy the press but I have a variety currently on order.

 

[243winxb]

The brass washer moving out of the correct position, is the only thing that drastically effects the powder drop charge weight.

Your powder is a very large flake. So there is going to be weight differences.

All you can do is operate the press in the same manner, every time the lever is pulled.

The mec bushing chart powder drop weignt is more for a progressive press, that drops powder at every pull of the lever.

The 600 jrs drop powder after many pulls of the lever. This settles the powder & gets more powder into the bushing.

 

[magshooter]

The brass washer moving out of the correct position, is the only thing that drastically effects the powder drop charge weight. View attachment 1020021

Your powder is a very large flake. So there is going to be weight differences.

All you can do is operate the press in the same manner, every time the lever is pulled.

The mec bushing chart powder drop weignt is more for a progressive press, that drops powder at every pull of the lever.

The 600 jrs drop powder after many pulls of the lever. This settles the powder & gets more powder into the bushing.

I do not have the brass washer in because MEC instructions say that it is for finer powder. I still don't understand even with the MEC Jr having may pulls of the lever before the powder is dropped the bushing is only so large how could it possibly fit another 2 to almost 3 grains of powder more?

 

[243winxb]

International powder

Having never used this powder, i dont have the answer.

Maybe try a test?
Without pulling the lever, drop a powder charge, weigh it.

Next place the powder bushing under the powder bottle to fill. Leave there while working lever 3 , 4 time to settle the powder in the bushing. Drop and check the weight, compare. Whats the difference?

 

[Milkmaster]

I used the "powder baffle" on my MecJr. It helped to make my drops more consistent. My bushing size ended up being one size larger than what came with the MecJr. My powder was a fine consistency. I also store my powder in a low humidity environment to make sure it stays driest as possible. I don't know if that helps for sure, but it seemed the right thing to do. Your results may differ.