View Full Version : Problem with MEC 600 12 ga

December 4, 2010, 01:32 PM
One of my MECs is acting up. It has been fine until now but has started putting a crease in some of the cases during the final crimp. one ounce load, WAA12SL. 20.5 grains WST.
Two shells - same press, same load. same session.

Notice the crease. Some of the cases have much less of a dent....just a line in the plastic that was not there before the crimp. Some of the shells are perfect.
What to do?

December 4, 2010, 01:42 PM
Pete, my friend, I suspect you may not be fully seating the wad, or it's backing out a little. So, when you go to crimp, the wad column is riding high. Instead of the wad settling down under crimp pressure, the case buckles. On the 600 jr. you can adjust for a little more wad pressure (what are you getting now?), or double stroke the wad setting operation -- set the wad, drop your shot, then back off a little (not enough to get the ram tube above the shot) and hit it a second time. This problem is more prevalent in smaller gauges where the wads may be really tight and trap compressed air.

December 4, 2010, 03:56 PM
Zippy: could be as you say. I have it set for zero or as low as it goes.
I'll add some.

December 4, 2010, 07:24 PM
i think you may get more responses in the reloading forum if you dont find what your looking for here

December 4, 2010, 08:43 PM
Those hulls appear, at least from the angle I see, to be of different lengths. I an finding different lengths with Winchester components that vary so great they are no longer my go-to hull in ANY gauge.......check your hulls, IF you have the same discrepancies I found, you will need to sort by length and reload accordingly. I needed to do that with my 28's - FOUR different lengths - all from Winchester......THREE different lengths in 20 gauge.........the frustration level and swearing at the press and component makers was misplaced - it was the hull maker who was to blame

.45 COLT
December 4, 2010, 10:53 PM
The creased hull sure appears shorter - crunched in the crimping process?

I would try the wad-pressure thing, but no more than 20 pounds of pressure. All wads will crush down some, given enough pressure, and Winchester wads crush easily. Then, a week or so later, if you've crushed the wad too far, crimps start to pop open as the wad straightens.


December 5, 2010, 08:29 AM
Sorry about the loss of the picture. Overly enthusiatic maintenance of the Photobucket account. Length....those shells were very very nearly the same length. The difference would be caused by the crease.

December 5, 2010, 10:32 AM
When I dropped my payloads, I also removed ALL wad pressure as it really isn't needed with modern wads. The wad DOES need to be seated without backing out, however. Are you short-stroking the downward stroke a little now and again?

You can adjust the crimp stage cam as well as the crimp die height.

December 5, 2010, 10:59 AM
Switch to the DRA 12 1 ounce red wad. It is slightly shorter that the Win wad and has cured the problem for most people. The hull crushing is a problem with the newer Win hulls when the hull is too full.