12G MEC 600Jr Mk 5 - what am I doing wrong?

P

pathdoc

New member
So I dug out the MEC, loaded up a bar and a bushing, grabbed a fired hull and got to work testing how much powder it would actually drop. I chose 700X and #8 lead Hummason shot. The hull is a once-reloaded Winchester Universal, but it doesn't matter; I was really only using it as a receptacle to receive the shot and powder.

The hull was run through the following processes:

Deprime/resize
Reprime (I put the expended primer back in)
Drop powder ---> the charge was weighed on a beam balance scale at this point and then dumped back into the powder bottle.
Drop shot ---> A wad was not inserted, but the handle was pulled, the shot was dropped into the hull and then poured back.
One pull to simulate the pre-crimp
One pull to simulate crimp finish.

The charge mostly stabilizes between 17.5gn and 18gn, which is good for almost all the load combinations I have in front of me (older IMR booklet), but there are intermittent and unpredictable excursions to 19gn, which constitutes an overcharge with the two types of primer I currently have.

I know I can almost certainly fix this issue by dropping back to a slightly smaller bushing, which should bring the intermittent overcharges down within the safe range, but I would have thought that after about a dozen simulated cycles it ought to have stabilized. I obviously can't take hulls through the full load cycle while I'm still waiting for the charge weight to stabilize, especially if it's throwing overcharges, but I am at least trying to simulate the full number of pulls that everything would go through to cause charge settling before the next one is dropped.

The inconsistency is infuriating! I might as well be weighing my powder and shot charges off the press and only using it to deprime, reprime, wad-seat and crimp. (I do have an adjustable shot-charge pourer and Lee dippers; I'm not entirely afraid to go down that route.)

What am I missing?
 
pathdoc said:
So I dug out the MEC, loaded up a bar and a bushing, grabbed a fired hull and got to work testing how much powder it would actually drop. I chose 700X and #8 lead Hummason shot. The hull is a once-reloaded Winchester Universal, but it doesn't matter; I was really only using it as a receptacle to receive the shot and powder.



The hull was run through the following processes:



Deprime/resize

Reprime (I put the expended primer back in)

Drop powder ---> the charge was weighed on a beam balance scale at this point and then dumped back into the powder bottle.

Drop shot ---> A wad was not inserted, but the handle was pulled, the shot was dropped into the hull and then poured back.

One pull to simulate the pre-crimp

One pull to simulate crimp finish.



The charge mostly stabilizes between 17.5gn and 18gn, which is good for almost all the load combinations I have in front of me (older IMR booklet), but there are intermittent and unpredictable excursions to 19gn, which constitutes an overcharge with the two types of primer I currently have.



I know I can almost certainly fix this issue by dropping back to a slightly smaller bushing, which should bring the intermittent overcharges down within the safe range, but I would have thought that after about a dozen simulated cycles it ought to have stabilized. I obviously can't take hulls through the full load cycle while I'm still waiting for the charge weight to stabilize, especially if it's throwing overcharges, but I am at least trying to simulate the full number of pulls that everything would go through to cause charge settling before the next one is dropped.



The inconsistency is infuriating! I might as well be weighing my powder and shot charges off the press and only using it to deprime, reprime, wad-seat and crimp. (I do have an adjustable shot-charge pourer and Lee dippers; I'm not entirely afraid to go down that route.)



What am I missing?
Click to expand...
Are you using a powder baffle between the bottle and press? Depending on powder type, I alternate between either a red plastic or metal baffle. Some powders don't require one.

Just a thought.

Sent from my SM-G781U1 using Tapatalk
 
Forget get the baffle for the moment.
(I just went through this issue this morning)
Solution below for best actual measurements

- Size/Prime the case
- Put the case on the scale and ZERO THE SCALE
- Pull case off scale (it will now register negative)
- Charge the case w/ powder
- Put the full case back on scale and look at net weight of the added powder

What's it read between charges now ?






OOC: What insert are you using for the 700X? #28?

.
 
Last edited:
While the red PC baffle is great, they are current unobtainable.
Another thing to do is to make sure you are using the same technique pulling the handle and sliding the bar so the vibration helps settle the powder
 
Sorry.... :( (lo siento mucho)
But the only way I could get consistent readings this AM was that "zero-the-case" method
(using an electronic scale)
 
A lot depends on where he lives, relative humidity, etc.
I have never found MEC's bushing chart to be correct when verifying drops. Typically I need to use 1-2 sizes larger. I use/have used Titewad, ExtraLite, Clays, Universal, Red Dot, Green Dot, WST, WSF, 452AA over the years (and a few more I can't remember)
 
FITASC said:
A lot depends on where he lives, relative humidity, etc.
I have never found MEC's bushing chart to be correct when verifying drops. Typically I need to use 1-2 sizes larger. I use/have used Titewad, ExtraLite, Clays, Universal, Red Dot, Green Dot, WST, WSF, 452AA over the years (and a few more I can't remember)
Click to expand...

The humidity and temperature have been shifting a bit from day to day out here (a part of Canada that has a different outlook on July 1 from the rest). As for the bushing chart, I wasn't even referring to it; I just went with the one I had and did some test weighs to see what it would drop. I think it was #29, but don't quote me on that.
 
#29's gonna drop close to 18gr of 700X
(trust me ;) )
MEC-Vol-Chart.jpg
 
How much does you press move is it mounted on a non moving bench.How many time do you cycle the press before you start checking charges it takes more than a few for the powder to settle.Everything has to be done the same way every shell.If a case sizes harder than the rest the following powder charge will be different
 
^^^^^^ Exactly and why I mentioned doing that above. If you slam the charge bar for dropping powder and shot, then do that every time (and it is preferred over going slowly); same thing for how you operate the handle.
 
wild willy said:
If a case sizes harder than the rest the following powder charge will be different
Click to expand...

How the hell do I control for that or prevent it? No way!

I thought to see just how long it took to stabilize and what the throw weights were like as it did. What I found immensely frustrating was that it immediately started to throw in the 17.5 to 18 range and stayed there over about a dozen charges, while I tried my best to do the same thing every time, but then it would throw these random overcharges a full grain clear of the rest.

I'm going to see if I have a #28 bushing lying around. Should be absolutely no way that can throw an overcharge relative to the load data I have, and I'll feel a lot safer if this is the case.
 
I have shot double charges of powder out of my 12 gauge remington 870, it hurt a bit and kicked me back to almost falling, but not damage or harm,, I have loaded shotgun shells for my whole life from 9 yrs old till 50,, we just picked up emptys on the range and loaded them, we just bought whatever wads were on sale, i cant imagine that 1 grain extra of shotgun powder is going to do anything, but, I am not an expert, and dont know all the implications., Im 65 now and have so many shotgun rounds loaded that i dont need any for many years, so take my advice for what it is worth.
 
The powder charge problem can be solved with a universal charge bar. The powder and shot ends have a small dial that allows you to adjust the openings to the desired weights of shot and powder. I've had these on my MEC 16-20- and 12 GA presses for the last 30 years. You still must use the techniques described herein, "slamming" the bar to slide in each direction, assuring the vibration will settle the load of powder and shot on an equal basis. The powder will generally drop up to +/- 0.2gr, so an 18gr load may drop 17.8-18.2 but with proper technique, that can drop to +/- 0.1gr.

Shot is different story. Because the shot bridges occasionally, the weight may vary by 1.25-2.5gr, which is equal to 1-2 pellets. 1-oz of #7.5 shot weighs 437.5gr, and #7.5 shot weighs 1.25gr each, so you can see weights of 435gr to 440gr if 2 pellets were missing or added. These figures will differ if you are using smaller or larger shot, but keep in mind, 1-1/8oz of #7.5 weighs 492.14gr (44 more pellets than 1-oz), so a 1-oz load of 440gr should not be a cause for concern.

What I cannot tell you is where to get this universal charge bar. I checked the MEC and MidwayUSA web sites with no success. My charge bars are unable to be removed to see if there is a name on them because all presses have shot and powder bottles full.

Surely there must be a colleague here who also uses these and may be able to reveal a source for purchase.
 
cdoc42, thanks. I considered the universal charge bar, but have never been that invested in accuracy and consistency. My shotgunning consists of casual shots at clays from a manual flinger, very often as a solo effort. It's not competitive at all. I'm more concerned with not overcharging my hulls than I am with ensuring that every charge is within 0.1gn and the velocity is "regulation" - if I actually shoot straight, the clays still evaporate.

If I were doing regular competition, it would be a very different story; the machine would be going constantly and the load would be more or less fully established and would never change. I wouldn't be having these dust-off-the-mothballs issues!
 
I get best results by operating the machine uniformly. Any extra jerk, bump or jarring can effect the powder charge, this goes for a Dillon or any other machine or powder measure. As for case sizing hard, I quit trying to load field hulls years ago(altho some of the Remington field hulls load ok now days). Stick to AAs or Remington target hulls and they load easier and better(they still have brass rims instead of steel). Federal target hulls may also be brass, I don't have any. I only keep AAs now days.
As usual, your mileage may vary.....................
 
pathdoc, I'm a bit perplexed. In your original post you said, "The charge mostly stabilizes between 17.5gn and 18gn, which is good for almost all the load combinations I have in front of me (older IMR booklet), but there are intermittent and unpredictable excursions to 19gn, which constitutes an overcharge with the two types of primer I currently have."

In your last post, you said you have "never been that invested in accuracy and consistency."

Accuracy is more dependent on your personal skill with whatever weapon and load you have. Consistency relates to reloading skill, and relates to safety as well as quality.

If you want to prevent unpredictable excursions in powder charges, you must concentrate on the consistency of your techniques as described herein, and/or seek assistance from ancillary equipment that reduces those chances of overcharge. When I first started to reload shotgun back in 1969 or so, being a neophyte, I overcharged my 12-GA loads with Red Dot. It did not create any damage but the sound of the shot alerted those around me such that they brought it to my attention I must have done so.

Early on, in rifle reloading, I found H4895 was not quite suitable for my .270 after my load locked the bolt.

So I think it would be wise for you to look toward minimizing the inconsistencies by maximizing the available solutions.
 
I would think that the universal charge bar will do nothing to help with your problem. Probably it will make them worse. I tried to make one run consistent for a couple of years. I have no trouble using the bushing bars and Tightwad powder. IF I can find it, and thats a big if, I’ll be happy to send you the universal bar. After you get disgusted with it you can throw it away. I have a hard time trashing something I paid hard earned money for.
 
You must log in or register to reply here.
Back
Top