View Full Version : Primer explosion in MEC 9000

April 1, 2006, 11:04 AM
Anybody ever have this happen? Last night I was loading 12 ga. shells on my MEC 9000. I'd done about 50 shells, when BANG! on the downstroke, a primer goes off. Scared the @#$% out of me. When the smoke cleared, I tried to determine what I'd done wrong. Never did find the primer that exploded, but I assume one dropped upside down and I failed to notice it before taking the next stroke. The good news is that I wasn't injured, and the press is no worse for the wear. Should have been more alert.

April 1, 2006, 11:26 AM
I had it happen on a Dillon 550B. My buddy was loading on it and all of a sudden Bang. Luckily it was the very last primer in the machine so no sympathetic detonation of the other primers occured. We never did find out why it happened but ESD (electro static discharge) was the theory.

Saw (heard) it happen on another 550B at a gunshop I used to frequent also. He had a full tube of primers and his ceiling tiles looked like a shotgun load hit them.

I've heard that some people will slip a short length of black steel (gas) pipe over the outside of the primer tube assembly for added safety. I never did but may now for the heck of it.

Glad you're ok. Potentially dangerous hobby, this reloading stuff.

David Berkowitz
April 1, 2006, 11:31 AM
I've never had it happen, but I worry about it alot.
How old is your machine and about how many rounds have you processed?
I have inadvertantly attempted to seat primers upside on several occiasons with no mishap, but I still worry.
If your machine is new, check for a burr on the seating thing.
I switched to the high capacity primer feed and have had far fewer problems.

April 1, 2006, 11:45 AM
I have not yet had the pleasure of having a primer go off on my MEC 9000..I actually watch every primer drop because I have had too many hit sideways or in some way not right. I have tried adjustments, but for some reason it still happens on rare occasion.

April 1, 2006, 12:46 PM
The MEC is about a year old and I've probably run 2-3k shells through it in that time. Never had a problem. I bought it right about the time MEC switched to the high-cap primer tray, so mine still has the older style. Was using Win 209 primers, which I've always used with good results.
I always try to watch every primer drop, because like ruger4570 said, no matter how I adjust the tube, I still have them occasionally drop sideways, or not completely seated upright in the hole. Seems like I would have seen one that was completely upside down, since after you do something for a long time, things that are unusual jump out at you, but who knows? I might have been not FULLY paying attention and missed it.
Maybe edward is right with his static electricity discharge theory. I load on a concrete floor and a wooden bench, but I suppose it could happen. I guarantee you I will be more alert next loading session!

April 1, 2006, 01:40 PM
209 primers seem to be well coated or sealed to the point that ststic would be much less likely than with a pistol or riffle type primer, that's just my personal observation and opinion. I always felt quite safe and secure with the 209's as far as handling. But an upside down or sideways lay could be totally different story. Are the pistol and riffle primers sealed as well as the 209'S? you can see the clear coating on the 209's and I use them in foul weather in my muzzleloader and they don't seem to get wet. The other style primers, they say don't handle with bare hands as they are sensitive to oils and moisture etc.

My mec is worn to the point that I have plenty of primer feed problems but have not used it in ages. Will the new style primer system replace all of the older style on all presses?

I hope you were wearing safety glasses. If not, I bet you do now. ;) This is a good post for all to see that crap does happen. I like the black pipe over the tube idea. Even pvc pipe may help.

Very glad to hear that you were not injured.! :D And thanks for the heads up warning.

David Berkowitz
April 2, 2006, 02:09 AM
I am fairly certain the new hi-cap primer system will fit and work on any MEC Progressive press.
I was so frustrated with the old system I was ready to trash the whole wretched thing.
There are still some problems with the new system but it is so much better.
I have learned to develop a rythem in loading, slow down just a little, and I can now reload several hundred rounds without a problem.
The new primer is adjustable for when the primer drops and is very easy to install.

April 2, 2006, 11:18 AM
I've never heard of a primer going off in a Mec.

Possibly, a pellet or some other "object" was in the primer seat? I'm not sure why an upside down primer would ignite. The handle would stop almost immediately.

Did you happen to spill any shot prior to this problem?

April 2, 2006, 03:02 PM
I must have been really lucky in all the 100's of thousands of rounds of shotshells and metallic cartridges that I have loaded, I have never had a primer go off. Knock on wood. :D I have squished shot under the primer cup, (wouldn't do it with steel shot) and crushed metallic primers sideways and have never had one pop.

Glad there wasn't any injuries.:)

April 2, 2006, 03:57 PM
I am nearly certain there wasn't any spilled shot in the primer seat. I had only loaded about 50 shells when this occurred, and hadn't had any spills prior to the kaboom.
Could have been a little powder (I was using e3) in there, but I've never had a problem before with a small amount of powder in the primer seat.
It still is a mystery. I might never figure it out, but I still gained from the experience because it taught me a valuable lesson in staying vigilant and cautious in every step of the reloading process. Not to mention the vivid reminder of the importance of safety glasses! :D