16ga.com ~ View topic

Joined: 24 Mar 2016 Posts: 72 Location: Louisiana

I have not used my med 600(jr as I recall) in years. It is set up for 12ga. To set up for 16ga steel, is it just a matter of a new charge bar and bushings? Do I need a. Steel charge bar? Please excuse my ignorance. I am now retired and have the time to resume loading. I would like to load shells with more velocity than factory offerings. I hope to get to 1400 to 1500fps if possible. Thanks.

Joined: 21 May 2010 Posts: 603 Location: Victoria BC Canada

I obtained a kit from the BPI agent in Canada. Perhaps MEC can do the same. I have found them very helpful.

Joined: 19 Apr 2008 Posts: 477

You'll need a conversion kit. MEC and some of the larger shooting suppliers should have one. All the tubes and crimp stations need to be changed. The bars and bushings are the tame. I converted a 12 ga 600 JR to 28 ga years ago. Not hard but it takes some adjusting to get it right.

Joined: 24 Mar 2016 Posts: 72 Location: Louisiana

Thanks, will look into it.

Member Joined: 02 Feb 2007 Posts: 371 Location: mpls mn

Once you get the die set you should be good to go,With steel shot and large lead or other no toxic ( larger than 6) I load them by hand. weighing every powder charge and shot charge. I use the press to prime re size and crimp.
I start with a reading powder measure dumping powder into the pan for my scale then adjust accordingly with a trickler.
I made my own shot scoops with 45 acp cases and 416 rigby cases cut to appropriate size with a soldered on bailing wire handle ( ala Dick Lowe) again I weigh the shot charge and adjust.
Once you get in a groove you can load a flat in no time.

Joined: 01 Feb 2016 Posts: 23

The conversion process is largely undocumented. While I haven't done this on a MEC 600; I have done it on my MEC Sizemaster.

The conversion kit will come with a new depriming punch, priming punch, new metal drop tube (probably a new plastic drop tube as well, but those parts are the same) and new crimp dies. Size-masters also come with a new base resizing collet. Your conversion kit on a MEC 600 may come with something similar. My conversion kit came with a separate shell plate and I suspect the MEC 600 conversion kits do too.

The depriming punch on the 12 gauge is noticeably wider than smaller gauges. The reason being, when the bar comes down all the way it flares out the crimp in addition to depriming the case. Flaring the crimp like this may or may not be necessary, but I suspect it aids the remaining reloading steps.

The priming punch is also wide to fit the greater diameter of a 12 gauge round snugly. 16 gauge shells won't fit on it. Both of these punches are very easy to replace. Simply swap them out and tighten them up with the same nut. The priming cup in the base of the machine is identical between gauges.

The drop tube can be a real pain to replace. You'll have to loosen the allen key holding it in place and push it all the way up through the top. That's a real chore sometimes, particularly when replacing it. You'll need to keep that key loose to adjust your depth and wad pressure (if any) when you get started.

Changing the pre-crimp die is simple and straight forward.

Changing the shell plate on the sizemaster is a pain, but fairly straight forward.

The final crimp station gave me FITS when I first did a conversion. Granted, I had only had the press for a few hours and only made a couple boxes of shells, so I wasn't terribly familiar with how that part went on or operated when I did the changeover. The important part to remember is that the screw needs to be drawn up through the top plate of the MEC in order to hold the die on securely. This may take some finagling, and you'll have to readjust this piece everytime you change calibers. I recommend keeping a factory shell on hand. Here's my steps for setting that up.

Screw the plunger all the way up as high as it will go. This will likely require you to move the lock nut down once or twice as the threads on the plunger are quite long. Now remove all the cam from the outer piece of the die. Refer to your instructions on how to do this. At this point, you should be able to place a factory shell in the final station and lower the die over it without altering the shell in anyway.

With a factory shell in the station and the die body lowered over it, adjust the plunger downward until you feel it firmly contact the shell. This should give you a rough ball-park idea of where the plunger needs to be for this type of shell. Now you can begin to carefully add cam to your crimp die a little at a time, testing each time. Once you see or feel it begin to operate on the factory shell, you should be in the ball park. Begin reloading and fine-tune the final crimp station as necessary.

I hope that helps you. I searched online everywhere I could think of for instructions on how to convert a MEC to a different caliber and found nothing, so maybe this will help you avoid some of my mistakes.

Joined: 18 Feb 2014 Posts: 30 Location: New Zealand

Wow. I've only done 2 conversions but on both occasions the die set kit from MEC came with easy to follow instructions. Took a while to get the bits on and then a while longer to dial in the crimp stations.

Richard.

Joined: 24 Mar 2016 Posts: 72 Location: Louisiana

Thanks for the detailed responses. This site delivers!

Joined: 23 Mar 2016 Posts: 11

Wow, I was thinking about this very question over the weekend and was going to ask about it as well.

A lot of good information on this thread.

For those of you that have changed over a sizemaster how difficult was it to convert the head sizing collet?

I plan on roll crimping my shells, so I don't need to worry about the crimping stations but I would like to convert my sizemaster over to take care of the sizing, priming, and wad ramming operations. With the exception of the sizing station, those should all be the same as the 600. Doesn't sound like it should be too bad of a job.