MEC Sizemaster (600?) Primer Feeder Problem

TheKlawMan · June 12, 2011, 03:39 AM

Can someone give me an idea how to adjsst the automatic primer feed on a MEC Sizemaster. I believe it should be the same as on the MEC 600 JR.

I bought this used one and checked it out before taking it and it worked fine, but the automatic feed was taken off for transport. When I reassembled the feeder it isn't picking up and dropping primers.

I have the intructions and they aren't too clear. After googling it it seems a lot of people complain about trying to set them up, they like them once set, but nobody ever explains what they did to get them working.

Thanks for any help you can give me.

zippy13 · June 12, 2011, 01:58 PM

Klaw, my MECs are a little different, but the principle seems the same: The key to the set up is to engage the ball chain at the correct joint. If too loose it won't drop the primer, and if too tight the arm won't fully return. The primer arm should be free to fully sweep within the reservoir. I found that an occasional light application of silicone lube helps keep the arm moving smoothly.

Eazmo · June 12, 2011, 02:00 PM

I looked but cant help, my grabber has the new style primming system.

Call MEC, they'll help you out. good people

Technosavant · June 12, 2011, 04:05 PM

The primer feed is actuated by the final crimp station. If the arm isn't moving at all, then it's likely because you don't have the arm resting on top of the final crimp die.

It's hard to tell from the photos, but you want to make sure the arm visible in your last attachment rests on top of the die. You may need to adjust the die a bit.

TheKlawMan · June 12, 2011, 06:12 PM

Yay! I don't quite have it but I can tell it will work. It is almost there but I have to fiddle with the change just a tad more.

I am so thick headed that I didn't realize for the lever to be acurated there had to be a shell in final crimp, but that you start by placing the first primer in station 2.

Edit: Yep. Tightened the chain 2 notches and it worked!

Technosavant · June 12, 2011, 09:15 PM

Great.

When I installed mine, I went from "now THIS is a weird design" before I understood how it went together (the directions are so-so), only to decide "this is a neat design" once I had it working. I was surprised how much easier life was with that primer feed. You wouldn't think going from individually placing each primer to a feed mechanism makes that much difference, but it does.

My only complaint is that when you get down to the last few primers (<10 remaining) they tend to slip away from the nose of the primer lever, so you have to keep moving them over to be picked up. I might not have mine adjusted perfectly, but I can't see what I'm missing if that's the case.

TheKlawMan · June 12, 2011, 10:30 PM

Techno, I just played with adjusting the powder drop of my adjustable bar against my scale while learnng how to read the power scale (a Lee Safety Powder balance scale). It seems accurate to around.05 grains.

The one thing I have to check is whether it is missing a part on station 2 (the primer insert), in which case I will get the right one. I only realized, after I kind of riveted a washer to the base of a hull, that the guy had three or four washers there to appartently adjust the height of the die.

Edit: I took a look at the MEC site and I was correct. The "primer pad" is missing and some washers inserted in its place.

June 12, 2011, 02:00 PM	#3
Eazmo Senior Member Join Date: April 15, 2011 Location: Arizona Posts: 164	I looked but cant help, my grabber has the new style primming system. Call MEC, they'll help you out. good people __________________ I'm just an average man I drive a average van My dog ain't got no pedigree!

June 12, 2011, 06:12 PM	#5
TheKlawMan Junior member Join Date: June 23, 2009 Location: Orange County, CA Posts: 2,149	Yay! I don't quite have it but I can tell it will work. It is almost there but I have to fiddle with the change just a tad more. I am so thick headed that I didn't realize for the lever to be acurated there had to be a shell in final crimp, but that you start by placing the first primer in station 2. Edit: Yep. Tightened the chain 2 notches and it worked! Last edited by TheKlawMan; June 12, 2011 at 07:15 PM.

June 12, 2011, 10:30 PM	#7
TheKlawMan Junior member Join Date: June 23, 2009 Location: Orange County, CA Posts: 2,149	Techno, I just played with adjusting the powder drop of my adjustable bar against my scale while learnng how to read the power scale (a Lee Safety Powder balance scale). It seems accurate to around.05 grains. The one thing I have to check is whether it is missing a part on station 2 (the primer insert), in which case I will get the right one. I only realized, after I kind of riveted a washer to the base of a hull, that the guy had three or four washers there to appartently adjust the height of the die. Edit: I took a look at the MEC site and I was correct. The "primer pad" is missing and some washers inserted in its place. Last edited by TheKlawMan; June 12, 2011 at 10:38 PM.

June 12, 2011, 01:58 PM	#2
zippy13 Senior Member Join Date: August 23, 2008 Location: SoCal Posts: 6,442	Klaw, my MECs are a little different, but the principle seems the same: The key to the set up is to engage the ball chain at the correct joint. If too loose it won't drop the primer, and if too tight the arm won't fully return. The primer arm should be free to fully sweep within the reservoir. I found that an occasional light application of silicone lube helps keep the arm moving smoothly.

June 12, 2011, 04:05 PM	#4
Technosavant Senior Member Join Date: May 29, 2007 Location: St. Louis, MO area Posts: 4,040	The primer feed is actuated by the final crimp station. If the arm isn't moving at all, then it's likely because you don't have the arm resting on top of the final crimp die. It's hard to tell from the photos, but you want to make sure the arm visible in your last attachment rests on top of the die. You may need to adjust the die a bit.

June 12, 2011, 09:15 PM	#6
Technosavant Senior Member Join Date: May 29, 2007 Location: St. Louis, MO area Posts: 4,040	Great. When I installed mine, I went from "now THIS is a weird design" before I understood how it went together (the directions are so-so), only to decide "this is a neat design" once I had it working. I was surprised how much easier life was with that primer feed. You wouldn't think going from individually placing each primer to a feed mechanism makes that much difference, but it does. My only complaint is that when you get down to the last few primers (<10 remaining) they tend to slip away from the nose of the primer lever, so you have to keep moving them over to be picked up. I might not have mine adjusted perfectly, but I can't see what I'm missing if that's the case.