Just now finished dialing in my 12 ga MEC650 adjustments to run the newer 2-piece AA hulls glitch free. I must have spent 5 or 6 months of futzing with it -- just for a few minutes every few weeks. It's not like I made a concerted effort of it. I just tinkered when I was in the mood and had some time.
Anyhoo, what a bunch of back and forth it requires (at least for me -- and others judging by internet threads)! I suspect it's part of a master plan by MEC to sell more reloading presses. They price 'em cheap enough compared to higher end Posness, Hornady, Dillon et al that you just add multiple machines instead of risking messing with your settings.
When I bought this one used ~6 years ago, it must have been set up for old style AA hulls. It would run the new AA hulls -- mostly.
This is a cutaway view of the old one piece hulls (may they rest in peace).
I just lived with the occasional bulged/wrinkled hull and cheated reshaping some of them in my supersizer (yeah I know, I know -- that's supposed to be a no no). After about 1500 loads that way I finally got fed up and got to reading up on it.
The wads don't sit down in the new 2 piece hulls like the old hulls. They need pressed into that tapered interior cup. Otherwise they don't set at the right depth down on top of the powder column.
Oy. It's a bit of an art form adjusting these -- or at least a secret decoder ring operation. There's a bit of back and forth from one station to another trading off adjustments. I see why so many guys set up for one hull and then leave it. Alone. Forever.
It can be a bit of a mess getting it figured out the first time.
I think I've got it mostly down now and could make a change over reasonably quick if I did it in the next couple weeks. A couple months from now? Yeah, prolly not. I'd almost certainly be mis-remembering stuff and have lost the knack.
The manual only seems to give you about 80% of the recipe. I did a lot of reading on the intrawebz and tried to glean the wisdom from the chaff.
I don't know if this is the right sequence or not but here's generally what I did. There was a bit of back and forth to get to this point.
Ya gotta break a few eggs to make an omelet. Quite a few if you're a bit clueless still on the learning curve.
First off I adjusted the wad pressure to set the wad down in the interior cup in the 2 piece hull. I went to 40 lb's recommended on line but finally backed off to 30 lbs because I was getting a wee crease showing on the hull.
Second I adjusted the crimp starter to leave an opening just a wee bit smaller than a pencil diameter. Mine is the old school style which is adjusted up or down by changing internal shim washers. I ended up working with pennies and dimes. I may go ahead and get the adjustable plastic starter at some point. It has a reversible insert or something for fast change from 6 pt to 8 pt. For now the old school metal 8-pt starter is fine.
Third I adjusted the crimp finishing station to set the crimp depth to match a factory load. I mreasured the depth from the crimp limp down to the fold on a 4 or 5 to get an average depth to set to. I was getting a nice star without any spiral but did have a bit more opening at the center than I liked. I left it for the moment.
4th I raised the final (taper) die a bit. It was set a bit low and was causing the hull to buckle on some shells. This was the main defect that finally got me to try adjusting the press.
5th I went back and experimented with the crimp starter again to try closing down the hole in the crimp center. This is where it got a bit futsy and (I'm sure) my inexperience got in the way. Swapping in different washers/coins, I choked the starter down but that wasn't the answer. I opened it up but that wasn't the answer. I set it back to where it had been leaving just about a #7 1/2 size hole.
Up to this point I had left the mysterious cam on the crimp finishing die linkage alone.
It was near one stop already so I set it to that stop and cycled 4-5 shells through. Nope. Ugly crimps. And so it went for several cycles of tweaking. Change the crimp starter opening, Move the cam. Stare at undesirable result. Then try again. I've got quite a few loads needing me to drip wax on crimp holes before boxing.
I wound up with the crimp starter leaving an opening just smaller than a pencil diameter and the cam back about 30% of it's adjust from one stop.
The trick was finding the right combo of crimp starter depth and cam position that finishes them just about perfect.
Good thing I don't do this for a living. /heh/
Yeah, still cheaper than therapy.