Primer tube detonation - myth or true?


December 4, 2007, 02:44 PM
I read about primer tube sympathetic detonation in Lee's reloading manual and I'm wondering how likely that is to happen with a popular press such as a Dillon XL650 or a Hornady LNL AP.

Has anyone here experienced such a disaster or personally know of someone who has? If so what were the exact curcumstances and consequences?

Internet rumors and third-party reports don't count. :)

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December 4, 2007, 03:12 PM
I had it happen twice on an Ammo-Load press. This press is a commercial, motor driven press, and will do about 1,500 rounds an hour. It uses a sliding bar to carry the primer from the tube to the priming station and if a primer gets cocked sideways, it smashes the primer and occasionally sets it off. With high volume loading, litterally thousands of primers go through the bar in a day's session. Primer residue can build up there and when a primer goes off, so does the residue, setting off the whole tube.

The first time this happened, the tube had just been filled and it blew the follower through the ceiling and ruptured the primer tube. The strong steel sleeve (blast shield) around the primer tube held, so I wasn't hurt, but the machine was slightly damaged.

The second time it happened, the primer tube was nearly empty and there was minimal damage to the machine. The blast tube confined the blast, just as it was designed to do.

The first time it happened, it was a "drawer changing event".

Hope this helps.


The Bushmaster
December 4, 2007, 03:39 PM
I bet you were cleaning that "mess" for quite a while. I think if I had a machine that did that ever once in a while I might think about investing in disposibles... I use the Lee Auto Prime II and have never had a primer feed tube problem. In fact I have never set one off when priming...

Mikee Loxxer
December 4, 2007, 03:44 PM
Only a third part account unfortunately. I did however see the hole left in the ceiling by the blast. The press is question was a Dillon progressive of some flavor.

December 4, 2007, 03:53 PM
It's not a myth, for sure!
If one goes off, you will have a detonation of the whole column.

I have heard of people being killed from dumping / storing loose primers in a glass fruit jar, and later dropping it on the floor.
It's about like a grenade going off.

December 4, 2007, 05:06 PM
LOL i remember as a little kid shooting pistol primers from my air gun. It was great fun until they came back at you.

Howard Roark
December 4, 2007, 05:53 PM
This happened about 25 years ago and I don't remember all the details.

A friends dad was loading on a RCBS or maybe a Lyman and managed to set off a couple of primers in the tube. All I remember was seeing the split tube and his bandage where he went to the hospital to get part of the tube removed from his belly.

My dad taught me well and I have always had lots of respect for primers.

December 4, 2007, 06:20 PM
I take it as there must be truth. Lee products state not to use Federal Primers.

December 4, 2007, 07:43 PM
Dillon Primer System Detonation ( The links to the pics are broken, but I still have them somewhere..unfortunately my computer was packed yesterday. If you want them, send me a PM and I'll email them in a few weeks when I get up and running again.


Zak Smith
December 4, 2007, 09:51 PM
I had a XL650 primer tube detonate-- don't worry, it sounds a lot worse than it was. The XL650 totally contained the "blast" and the safety features worked well. It was loud and smelled bad. A few primers stuck in the ceiling. Dillon sent all the replacement parts necessary. The problem was a primer which somehow got sideways in the XL650's primer-transport disc.


December 4, 2007, 10:00 PM
On a 650 if it detonated while being seated on a brass case it would be at least a few inches from the tube. How could it cause the rest to detonate?

December 4, 2007, 11:22 PM
The 650 priming system has several primers in the disk between the tube and where they are seated in the cartridge. These are close enough to chain react all the way back to the tube. The pics I've seen of one blown up showed that the system was damaged by the blast, but held intact and vented most of the blast up the tube and away from the user.

That's one reason I always wince when folks talk about putting a heavy metal follower rod in their primer tube to show them when the primer tube is almost empty. That extra weight could be enough to cause the tube to rupture, rather than vent safely out the top.


December 4, 2007, 11:33 PM
Instead of a metal follower rod, I use a 1/8" wooden dowel. It weighs hardly anything at all and I've got it marked at 25 primer increments. Works like a charm on my Hornady Pro-Jector and RCBS bench priming tool.

Hope this helps.


Zak Smith
December 5, 2007, 12:44 AM
Dillon's own empty primer-tube alarm comes with a lightweight plastic rod. In fact, seeing it melted and bent in half on my bench was the first clue my event wasn't just a single primer detonation.

December 5, 2007, 10:17 AM
Lee hand primer. nuff said.

Pump Gun Pimp
December 5, 2007, 03:20 PM
The pic of the Warning that ATAShooter posted is from a Hand primer ( Lee Auto prime ). And it says watch out for explosion.

December 5, 2007, 03:36 PM
I use a Hornady hand primer frequently and I have always wondered about a chain detonation. There is a continuous line of primers from the seating mechanism to the hopper and the hopper will probably hold a couple of hundred or more primers. If that thing went up you would be in a world of hurt.

Travis Two
December 6, 2007, 02:24 PM
I had one go off on one of my 650s when I crushed a primer while loading .45 acp and the case had a crimped primer pocket and I forced it. The noise was a wake up call but the primer tube held and shot the plastic rod up and it dented the drywall when it hit but that was the extent of the damage. I need some pieces from Dillion to repair the prime system and they provided that free of charge. Since then I've learned not to force that handle if it feels wrong while seating the primer. But I have to admit that the blast tube held just fine and there was no serious damage except to my ego.

December 8, 2007, 10:04 AM
I've had a few primers blow in my Dillon 1050 due to improper adustment of the primer crimp swage not removing the crimp, but the detonation happens in the slider bar as the primer punch attempts unsuccessfully to jam the primer into the primer pocket. It stinks and messes up the process, but after proper cleaning the press is right back at it.

I haven't had one detonate in the tube.

Too the primer system on my press definitely favors the CCI primers, as sometimes the Winchester small rifle primers don't want to go through the tube properly. Perhaps it is some sort of dimensional consistency issue?

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