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Joined: 21 Mar 2015 Posts: 3

First post here but I have found a lot of good I formation in these forums when I first started looking at getting into reloading.

I recently bought two presses from a family member who was given them by a family friend who passed. All that to say the person knows nothing about the presses. The one is definitely a 650 progressive, the other is either an older 600 jr or a 700 versamec.

The pictures in the mec owners manually make it seem that I have a 700 based off the open end of the base being in the front with the height adjustment bolt being in the back. Also, mine has metal dyes where the 600 jr seems to consistantly have the poly/plastic parts. However, a lot of presses I've seen for sale by private owners are advertised as being 600 jr but the pictures have the same base and dyes as mine.

I can add pictures if needed. Any clue how to tell the difference between the two? It only has three base screws so it's definitely not the newer 600jr mark 5.

The reason I need to know is that it's set up for 20 gauge and I need to get the conversion kit for 12 gauge. Thanks ahead of time for any help.

Previous to the 600, MEC single-stage loaders were the 300 Speeder, which had a full length die like the newer Ponsness Warrens now have, and its successor, the 400 SuperSpeeder, which had a re-size ring like a 600, and a crimp system that involved a sleeve, but used a closing plunger that did the job sorta like a 600, but not quite -- kind of a half way between the 300 and the 600. They also had their first progressive, the 500, which had the leverage system from the 300 and 400, and a crimp system a lot like a 400, but had a manually rotatable shell carrier and a manually shuttled charge bar. Then they upgraded this 500 progressive with a feature that cocked a charge shuttle spring with a manual release, and a new crimp arrangement that continues to this day, though the dies were metal. They also put on a better lever linkage system. They called this upgraded progressive the Super 600, and sold the Case Conditioner as a convenient reszing partner for those that wanted to re-size without making changes to the reloader. They created a brand new single-stage reloader with the same lever linkage and crimp system as this upgraded progressive, and called it the 600 Jr! So the top of the line progressive was the Super 600 and the top of the line single-stage was the 600 Jr. Now you know where the Jr. came from!

People had trouble with high brass hulls in the 600 Jr., as it's cam system to eject the shell from the ring resizer did not quite have enough stroke to push the tallest brass all the way out. So they altered the cam and the eject rod to get more ejection stroke. They put this feature on the 600 Jr. frame, as well as the infamous Pro-Check, a little device intended to make the charge bar sequencing fool-proof, and called it the 700 VersaMec. If you want to see the difference between a 600 and a 700 go to the parts lists on the MEC Reloader site. If your unit has what is basically a hex head bolt for an eject rod, it is a 600 Jr. If it has the inverted U-shaped rod and the three-bolt base, it is a 700. If it has a 4-bolt base it is a 600 Mark 5.

In '82 they changed the knockout bushing details, went to plastic dies and wad guide, which were all previously steel. The 700 followed along in time similarly, but again, it had the Pro-Check device and the different eject rod and cam for tall brass. In '86 it appears they discontinued the 700 and incorporated its features, the Pro-Check and the eject rod and cam for tall brass, into the 600 Jr, calling it the 600 Mk 5. In addition, that's when the bases went to the 4-bolt style, and the crimp starters went from the old metal Spindex to the modern day plastic one. All crimp dies are interchangeable for all years of 600 and 700, as re crimp starters. The Pre-82 reloaders have differences, again, in the knockout bushing details which are hard to see, but make those parts not interchangeable. Wad guides after 82 are a plastic unit, and are interchangeable with older systems only if you get the wad guide bracket that matches. The plastic dies (Delrin?), are a fiber reinforced plastic, and are extremely tough, do not corrode, and stay clean and smooth. They will be trouble-free for a very long time. Steel crimp dies seem to be shaped differently inside depending on their vintage. I think some are better than others, but it's a real nit about which you needn't be concerned. You can put the eject rod from a 700 or a 600 Mark 5 on an earlier 600 Jr, no problem. If you do, remember, the eject cam needs to be changed too.

I hope this answers the 600/700 questions. These are marvelous reloaders for which you can still get parts for any vintage. When you order parts or die sets, talk to MEC service. They will make sure you get the right parts, as the die set kits are a little different for the different years.

Now, about those Super 600's -- the progressives. They are somewhat rare. MEC developed that into the popular 650 by adding a completely automated charge bar shuttling system. It is possible to convert a Super 600 to a 650. The next step was the Grabber, which is noting more than a 650 built to incorporate a collet resizer, so resizing does not have to be done as a separate operation, out of the progressive sequence, as in the 500, Super 600 and 650. Having made the collet resizer, MEC then made the SuperSizer unit as a collet resizing partner to the 650, and discontinued the old Case Conditioner ring resize/deprime unit, which incidentally had a lot of 600 Jr. parts in it. Automating the shell-holder turned the Grabber into the 9000. Having the collet resizer, MEC then added it to the 600 to producing the SizeMaster. It appears MEC tried or tries to migrate everyone to the collet resizer. My opinion, of course, is that the collet resizer is superfluous to the needs of a single-stage reloading system, but that's been debated before. Anyway, MEC still gives you the choice, which is nice.

There is another series of MEC's, the 250 and the 310. They came out about the same time as the 600's, and were intended to be the inexpensive bottom of the line. They had linkages like the old 300, 400 and 500, and frames something like a 600. They used crimp systems something like the old 300. I think they were pretty schlocky. You don't see many. They look like they were almost as costly to make as a 600 -- loss leaders. I've never used one. They'd be better than a Lyman EasyLoader or the Lee Load-All, but kind of in that same category. As I see it, there's never a good reason to have anything less than a 600 Jr. or even an old MEC 400 SuperSpeeder if you can find one. There are lots of excuses, but no good reasons for anything less capable, if what you wanted to do is reload enough shells and good enough shells to obviate the need for factory loads.

Joined: 21 Mar 2015 Posts: 3

Thanks so much for the reply and the wealth of information! Good advice looking at the parts list. I was going by the pictures on the owners manual. The discontinued 600 jr manual must be the 82-85 model which has a different base style.

It appears that I have the pre 82 600 jr.

I do plan on running high brass through it some. Any solutions since this was before they figured that part out?

Joined: 28 Aug 2014 Posts: 924 Location: Eastern Tennessee

In the high brass resizing world I have never found the ring to be suitable for tightly spec gun. I just waited for a good deal on a super size and not had 1 issue since.

Joined: 21 Mar 2015 Posts: 3

I also got a super sizer with it that I can use for the resizing part. Never thought when I first started looking into this it there would be this many decisions to make. Thanks for all the help!

If you want to do longer brass with an older 600 simply buy the eject rod and cam for the current 600 and install it. That would be the inverted U or J shaped eject rod. Make sure you get the cam that goes with it, as it is not the same as the old one that works only with the hex-head bolt style eject rod of the old 600.

Tight chambers and the ring resizer -- Those of you having problems and think your have a "tight spec" chamber, why not make some measurements and move out of the world of speculation and into the world of facts. Here's a listing of chamber dimensions: http://www.dave-cushman.net/shot/shotshellloads.html You'll need a bore gage to tell what you're doing. Note that chambers are tapered -- are your shells? Yes, I suppose there might be a "tight chamber" out there, but by how much.

Most cases where re-loads will not drop into the chamber are from:

1) Dirty chambers -- a problem with some automatics
2) Belled-out crimp edges -- a loading technique problem
3) Improper resizing with ring resizers -- improper depth setting of the ring

Start with a good clean chamber, see if that makes a difference. Then get a vernier or digital or dial caliper and measure some factory loads that drop in. Measure the crimp end as well as the brass, both at the top of the brass and down near the rim. Set your ring resizer down so that the smooth non-printed portion of a credit card will just barely slip under the ring when the handle/lever of the 600 is all the way down. Run some of your "troublesome" hulls through the ring resizer. Run some of your non-troublesome hulls through, too. Compare the measurements of the brass of those resized hulls to the factory loads. You will find a few thousandths variation one batch or one manufacturer to the next on factory loads. You'll usually find the MEC rings resize the brass to the high end of that range. Again, I refer you to this source: http://www.dave-cushman.net/shot/shotshellloads.html . I find that factory set MEC collet resizers wind up with even greater dimensions than their ring resizers! You can set them tighter, but most people never do, and think they are doing a tighter re-size job because they read somewhere the collet was just better. Well the collet is the best way to go for a progressive reloader, and that's why we have them, but that's another story. Yes, there are some MEC resize rings that I think have too great or too little radius on the leading edge of the hole, but that's pretty rare. I suppose you could wear one out, but in 50 years I haven't.

Now start measuring the diameters of the crimp ends of your hulls, and maybe even some places along the length of the reloaded hull. Compare those with the factory loads. Here you will find most reload will measure much larger, and with more variation than those factory loads. One piece molded hulls like the Winchester-Western compression formed hulls, or the various Remington-Peters one-piece hulls retain their shape the best and 8 point crimps come out more round, naturally. Good luck finding those hulls in 16 gauge, however. Look at the shape and profile of the crimp ends of your reloads. That's the source of most feeding/chambering problems. Learn to use the MEC crimp system to round and taper the finished crimp.

If your shells offer resistance to chambering, try to figure out at what point of insertion the resistance really starts. That will lead you to the source of the fit issue.

OK, back to resizing -- Springback? Yeah, Yeah, Yeah . . it seems to be a little more with thicker steel heads than old thin brass heads, but not much. Again, if you think that's your real problem, make some measurements. Anything you resize involves yielding of the case head, and any resize method involves elastic "springback" of the material, whatever it is. To really analyze the problem you would need to know the diameters of the head before resize, the resizer diameter, and the modulus of elasticity and yield strength of the head material. It actually has more to do with case head thickness than it does with whether its brass or steel. Either way, it's part of the deal no matter what type of resizer is used. Yes, you might be able to choke down a collet resizer to get back to absolute minimum dimensions. Have you tried it? Have you closed the collet all the way down to its minimum? I have, and have still found collets that will not resize to the minimum factory dimensions. The only time I can do that -- and I really don't want to -- is when using a 28 ga. collet to resize 24 ga. hulls. But that's another story.

I failed to make a certain point in the above. Comparing the diameters of factory brass to the chamber dimensions in the article to which I published a link, you will find there is a pretty large clearance. It's not like a rifle -- shotshell cartridges fit pretty loosely. The upshot is you usually don't even need to resize down to factory dimensions for your shells to easily drop into the chamber -- and I mean drop in, as in kerplunk! A properly set resizer, whether ring or collet, will get the job done on steel or brass heads.

The rest of the shell? Paper or plastic can produce surprising resistance to chambering if it has swelled due to firing or some other reason. You can't resize it (no matter what Ponsness Warren says), but you can do things during reloading t0 insure it stays in the best shape possible, especially at the crimp end.