I was getting a severe swirl in my crimps from my MEC 600 JR. on most any brand of hull I was loading. Tried all of MEC's solutions but nothing solved the problem. The crimp starter was properly installed and rotated freely. I tried one day to make a shallower first crimp by not pulling the handle all the way down and a miracle occured. Perfect crimps on any hull. I adjusted the crimp starter UP all the way and replaced the factory nuts (1/4x20 thread) with thicker nuts which allowed clearance below the bracket to get an open end wrench on the nut and along with the top nut tighten securly. The starter is free to move and my crimps are perfect on both STS and FEDERAL hulls. Apparently the initial crimp was too severe an angle.
Would the Power Skiver available from Ballistic Products be capable of reconditioning the hull in the thread above or is there too much "memory" in the hull mouth? I am considering purchasing one to reshape the ends of my "swirled" hulls. Dave Hunt
I agree 1% is not bad and seeing that 90% of all my reloads are shot by my Sons who shoot for the High School trap team, I inspect every single shell and toss the questionable ones in the "my shells" bin.
Since I started reloading two years ago, I don't know how many thousands of rounds I've loaded, but I've only had one misfire and when I cut it up, there were no signs of any issues. Even the primer was dented.
I just always wondered what could cause the bad crimp, as well as if they were safe to shoot.
From the picture of the single shell, the problem is likely caused by the pre-fold crimper's grooves not lining up properly with the hull's crimp folds. It doesn't appear to be an excessive component length problem. Just confirm that the pre-fold is very free to spin.
If the 1% reject rate is an issue, line up the pre-fold's groves with the hull's crimp fold lines each time before crimping (I assume the MEC pre-fold has external ridges as the Hornady 366's does).
There's a website article (link above)that talks a little about this problem.
Or the crimp starter on the machine is free turning so it catches the old folds in the factory crimp. The crimp starter on the machine just did not rotate and catch the old crimp folds. It happens. Whether it was the shell or the starter crimp????
It just looks like the starter did not follow the old crimp and tried to create a new bunch of pleats. The old ones didn't like it much.
It may be that the shell (hull) itself is a little taller (longer) than others. I have read somewhere that Remington STS or Nitro hulls (which I prefer and use exclusively) as well as Federal and Winchester hulls have a slight variance in length...not many, but maybe the suspect 1 out of 100. I have seen the same crummy crimps from time-to-time (about 1 in 100 to 200) and I suspect the longer hull is the culprit. I just shoot the mis-shapen crimped shell and pitch it. Best Regards, Ed
Sometimes you will get a hull with a smooth portion instead of a nice 8 point opening. What has happened is that the plastic has gotten too hot in that area. These hulls will never crimp right and look very similar to the one pictured. Tony