School Me on MEC 600's

Shotgun Ammunition Reloading.
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Synchronizor
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Re: School Me on MEC 600's

Post by Synchronizor » Thu Jan 18, 2018 5:31 am

Glad to hear it.

If you're looking for data, check out Hodgdon's reloading website. Lots of good data with nice velocity/pressure ranges for a ton of component combos using Hodgdon, IMR, and Winchester propellants. A whole lot of my loads come from there.

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Re: School Me on MEC 600's

Post by Scorpion8 » Thu Jan 18, 2018 11:48 pm

Synchronizor wrote:
Thu Jan 18, 2018 5:31 am
Glad to hear it.
Thanks. I'm hunting powder bushings now, a trait not similar to anything in metallic cartridge loading where each load is dropped straight from a measure. Normally in reloading my metallic cartridges I spot check every 10th drop after the powder measure is adjusted. I have read a few places where folks drop or measure individual charges for shot shells, but it seems like that would slow down the process incredibly. Are the MEC powder bushings that wide in variation from drop-to-drop? It seems (famous last words) that a strict volume measurement drop via the charge bars can't vary too much, or am I missing something?
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Re: School Me on MEC 600's

Post by Synchronizor » Sun Jan 21, 2018 7:00 am

I think powder densities can vary from lot to lot, and environmental factors like temperature and humidity may complicate things as well. How you work the charge bar and other vibrations or jostling to the press can also influence how the powder settles into the cavity, and affect charges. Obviously, a specific propellant's grain shape and flow characteristics play into this. I've heard it recommended to develop a pattern to how you work the press, and do everything the same way each time to minimize this variation. There are also powder baffles you can buy that are supposed to help with this.

I don't do much measuring strictly by volume, personally, so I'm not super experienced here. I prefer to hand-measure propellant charges, using a dipper that I know gets me slightly below the desired charge, then trickling it up to exactly what it's supposed to be. Not as fast as other methods, but really not all that slow once you get a process figured out. I can load a hundred or two shells in an evening, which is enough for me. I like the extra precision too, especially for things like the recoil test loads I use for product reviews, which I want to be very consistent.

Plenty of folks load using those bushings, so it can certainly be done. Just check your charges occasionally, and maybe pick middle-of-the-road loads, where a few grains more or less of propellant won't result in anything unsafe. There's also the afore-mentioned universal charge bar, which will let you dial in a cavity size for a specific lot of powder, temperature, alignment of the planets, etc. Or, if you have some other stand-alone powder measure that you are already familiar with, there's no reason you can't use that for your shotshells.

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Re: School Me on MEC 600's

Post by Scorpion8 » Mon Jan 22, 2018 10:20 pm

Synchronizor wrote:
Sun Jan 21, 2018 7:00 am
I don't do much measuring strictly by volume, personally, so I'm not super experienced here. I prefer to hand-measure propellant charges, ....
And I think that's the confusing part. Several YouTube videos all state not to "thoroughly trust" the load-by-volume system of shot shell reloaders, kind of like you state above. But the system is set up to load that way. Even metallic cartridge powder measures get off or drift, but (in my 30+ years experience) not enough to do harm. Usually no more than 0.2-0.3 grains. So it seems like some advice is to NOT use the machine the way it was intended or designed, but don't you think the designers knew that also? In my browsing< I've yet to see a shot shell press that wasn't the drop-by-volume method, whereas any single stage metallic press can be dropped by the powder measure, dropped by an electronic powder measure, individually hand-trickled, etc. In my experience in rifle-caliber metallic cartridge loading, I check every tenth powder charge dropped by the powder measure, and have never had reason to be too concerned about small variations. I'm not a benchrest shooter, so minute variations are not critical to my hunting loads.

I understand the "develop a rhythm and method" of reloading, and do everything the same (same level of effort on the press arm, same amount of dexterity with the machine, same amount of finger drumming to Jethro Tull tunes on the workbench, etc...) but if you do all of those, shouldn't the shot shell machine be inherently accurate enough in reproducing a load to (a) not get you killed, (b) not get the guy next to you killed, or (c) make one miss high and the next miss low for the same aiming point?
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Re: School Me on MEC 600's

Post by Synchronizor » Tue Jan 23, 2018 3:57 am

Like I said, there are different elements that can play into it, and the flow characteristics of a particular powder are certainly a big factor in consistency. As I'm sure you know, some propellants meter more or less consistently than others. Like you mentioned, you need to watch for drift, and for variation, both of which are reasons to have a system to weigh-check your dropped charges occasionally.

Variation shouldn't be a big deal so long as you know what to expect due to your equipment, technique, and propellant; and select your load data so that the extreme spread of that variation all falls within safe bounds (both too-heavy and too-light charges can be dangerous). This is one reason I like load data to be formatted with a range of charge/velocity/pressure points for each combination of components, like in the following example for 12ga Federal GMM hulls from Hodgdon's website:

Hodgdon Internat'l Win. 209 WAA12L 23.5 7,500 PSI 1,300
Hodgdon Internat'l Win. 209 WAA12L 24.3 7,900 PSI 1,350
Hodgdon Internat'l Win. 209 WAA12L 25.5 9,100 PSI 1,400
Hodgdon Internat'l Win. 209 WAA12L 27.0 10,600 PSI 1,450

Drift is potentially more of a problem, though if you're using fixed powder bushings rather than adjustable charge bars or powder measures, you'll probably not see too much of that. Do remember to re-calibrate for new lots of powder, though.

Honestly, if you have experience measuring out powder for metallic reloading and keeping an eye on your charges to avoid issues, doing the same for shotshells shouldn't be that big of a hurdle. One thing you can do with the MEC 600 presses as a broad-strokes check for each round is keep an eye on the force gauge when you seat the wad over the powder. A serious over- or under-charge will register as a change in seating force when the handle is all the way down. I've caught a couple double-charges this way in my time.

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Re: School Me on MEC 600's

Post by Scorpion8 » Tue Jan 23, 2018 5:09 pm

Synchronizor wrote:
Tue Jan 23, 2018 3:57 am
A serious over- or under-charge will register as a change in seating force when the handle is all the way down. I've caught a couple double-charges this way in my time.
That I can understand, but my engineer-brain also has issue with it. A double charge is unlikely to occur unless I'm pulling the hull off the press for some reason and get out of step in my process. If the hull stays on the press, it would take two drops of powder to get an overcharge, and you have to cycle to the shot side in order to get to the 2nd drop of powder so that hull is going to have obvious charge issues as you handle it, since there would be powder-shot-powder even if you didn't add a wad. Otherwise, since the powder meters thru a powder bushing of a "fixed" volume, poorly metering powder can only ever drop less than the desired amount. Its not possible for the volume cavity in the powder bushing to get overfilled, because moving the charge bar scrapes off the overflow amount. All the more reason NOT to be pulling hulls off the press to meter or drop individual charges. I've examined the press working closely (again, the engineer side of me) and the powder-wad-shot drop station on a MEC-600 is the one in dead-front-center. It seems like once you develop a feel for that 3 step process and get used to the resultant wad-height and shot level near the top of the hull, then it's an easy quality check as the hull moves along. Again, I don't see how I could ever get an overcharge of powder as long as I'm not pulling the hull out of the reloading cycle and getting out-of-sync. It almost seems like you're better off using the press as designed, instead of thinking you need to do a different process than the press designer actually designed that press for.

Certainly, am not doubting anyone's years of experience, since I haven't even loaded my first hull yet. But intuitive questioning will resolve issues in my mind where I can decide to go with the process, or know where I have to modify the process.
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Re: School Me on MEC 600's

Post by Chilly » Thu Feb 14, 2019 3:04 pm

I think the manual's caution abouy not trusting bushings means to not simply go by the chart that gives APPROXIMATE charge weight for a given powder through different bushing sizes. Sometimes the chart is accurate, sometimes way off. Before trying a new load throw ten charges to settle the powder, then weigh a few charges. You may need to adjust a bushing size up or down to achieve the WEIGHT prescribed by the manual. After that I just pull the handle and keep my powder bottle between full and 1/2.

Big point to new loaders: the load recipe calls out the WEIGHT, NOT A BUSHING SIZE.

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