First primer detonation.

[Rich 10mm]

I actually got back to it last night. When the primer wouldn’t go in smoothly I just chamfered the pocket a little and they go in just fine. Thanks guys.

 

[FROGO207]

I was going to suggest it was a crimped case that got by the crimp removal step. I have had a couple of those over the years but figured it out before I popped a primer. Note:: I have mangled a few over the years bad enough that you couldent even recognize it was a primer and none have gone off.
I will admit I have not set off any YET!

 

[Virginia Jim]

Remember when you were a kid and you let a firecracker go off in your hand? Yeah, it’s like that.

 

[ms6852]

I've never have had it happened yet, but I'm sure if it ever does, a change of underwear and possibly pants are in order, depending on volume.

 

[Havok7416]

I set one off on my Dillon years ago while DE-priming some .30-06 left over from WWII (I was pulling the rounds apart due to bad powder). I ended up about halfway across the room before I figured out what happened, but other than that it was just noise.

 

[Waterboy3313]

Hopefully skid marks in your shorts was the worst of it.

I'm pretty new to reloading and I use a Lee single stage press and prime on the press. I remember my first reloading session I was scared to death. I wore my safety glasses as always plus my welding gloves on the hand I was pulling the lever with and my ear muffs while standing as far back as possible. The safety prime system can be a pita but I've stuck with it and any primers oriented in the wrong position are easily spotted. No issues so far but I would imagine one day the possibility of it happening is probably fairly good.

 

[1976B.L.Johns.]

I'm sure some guys develop a feel for priming on press,

Yup, and take your time.... it is not a race.

 

[Obturation]

Yup, and take your time.... it is not a race.

I always take my time, what little of it there is.

 

[sparkyv]

Loud, ain't it?

 

[Obturation]

Bob: "I had a problem using method X."

Joe: "That's why I only use method X. I don't want problem. You can get problem using method Y. You should use method X."

Joe's comment is odd.

Nothing gets by you.
I'm not nitpicky but I'll explain it in a way you may find less odd.
The point of my comment was to say that I use a hand priming tool to avoid unintentionally crushing a primer because I can get a good feel for what's going on. That would lead most folks to conclude that i mentioned it because the OP had an issue with such a low torque tool, which is what I also choose specifically to try to avoid crushing one (clearly that didn't work for him). Seems relevant to the conversation from where I'm sitting, but since you think it's odd that I added my two cents I'll try to be more normal.
@Texas10mm gave a response to my comment that was helpful and informative, yours made it obvious that you missed my point completely.

 

[ATLDave]

That would lead most folks to conclude that i mentioned it because the OP had an issue with such a low torque tool, which is what I also choose specifically to try to avoid crushing one (clearly that didn't work for him). Seems relevant to the conversation from where I'm sitting, but since you think it's odd that I added my two cents I'll try to be more normal.

I didn’t say you were odd, just the comment. But I wouldn’t take too much offense at that, as I’m a bit of an odd duck myself.

But even this explanatory response seems premised on some questionable logic. The assumption that “torque” and “crushing” a primer is what ignites them is, I think, wrong. I have flattened quite a few primers with my “high torque” presses, and have never popped a primer. That’s because priming compound generally requires a jolt to ignite, not mere smushing.

As to the notion that a lower-leverage device is less likely to pop a primer, I think that is precisely backwards. First, consider how a lever works. You move the long end a long way to move the short end just a little... but with greater ability to overcome resistance. On a press, the handle end of the lever moves several inches to push a primer less than a quarter of an inch. That seating ram is actually moving quite slowly - if inexorably. It will very slowly and calmly flatten a sideways primer. And not pop it. A lower-leverage device, such as a hand primer, is necessarily moving the priming arm much faster relative to the handle/lever motion. that factor alone makes handheld more likely to pop a primer.

That gets compounded by the same phenomenon that makes a dull kitchen knife more dangerous to the cook than a sharp one. Sharp knives cut with minimal muscle force applied to them. They don’t get “stuck” while you build up exertion against them and then suddenly overcome the food’s resistance with a violent motion - but dull knives do.

I asked the OP where his jolt came from. It seems obvious it came from a crimped pocket that he built up force against and then moved/bent/swaged/slipped enough to let the primer and seating arm suddenly jump forward - like a dull knife finally pushed hard enough to get through the food. Like a suddenly moving knife plowing into the cook’s left hand, the primer and seating arm, now moving fast, suddenly ran into the bottom of the pocket or another snag. There’s the jolt, and thence the pop.

Could that have happened on a press? Yes. But a hand primer doesn’t do anything to reduce the likelihood and, instead, probably makes it more likely.

 

[Obturation]

I didn’t say you were odd, just the comment. But I wouldn’t take too much offense at that, as I’m a bit of an odd duck myself.

But even this explanatory response seems premised on some questionable logic. The assumption that “torque” and “crushing” a primer is what ignites them is, I think, wrong. I have flattened quite a few primers with my “high torque” presses, and have never popped a primer. That’s because priming compound generally requires a jolt to ignite, not mere smushing.

As to the notion that a lower-leverage device is less likely to pop a primer, I think that is precisely backwards. First, consider how a lever works. You move the long end a long way to move the short end just a little... but with greater ability to move things. On a press, the handle end of the lever moves several inches to push a primer less than a quarter of an inch. That seating ram is actually moving quite slowly - if inexorably. It will very slowly and calmly flatter a sideways primer. And not pop it. A lower-leverage device, such as a hand primer, is necessarily moving the priming arm much faster relative to the handle/lever motion. that factor alone makes handheld more likely to pop a primer.

That gets compounded by the same phenomenon that makes a dull kitchen knife more dangerous to the cook than a sharp one. Sharp knives cut with minimal muscle force applied to them. They don’t get “stuck” while you build up exertion against them and then suddenly overcome the food’s resistance with a violent motion - but dull knives do.

I asked the OP where his jolt came from. It’s obvious it came from a crimped pocket that he built up force against and then moved/bent/swaged/slipped enough to let the primer and seating arm suddenly jump forward - like a dull knife finally pushed hard enough to get through the food. Like a suddenly moving knife plowing into the cook’s left hand, the primer and seating arm, now moving fast, suddenly ran into the bottom of the pocket or another snag. There’s the jolt, and thence the pop.

Could that have happened on a press? Yes. But a hand primer doesn’t do anything to reduce the likelihood and, instead, probably makes it more likely.

That does make sense.

 

[Old Stumpy]

Only with the Lee Loaders back in the early days.
You get a little carried away with the old plastic-tipped hammer as you start building up speed.

Whack, whack - one,
whack whack - two,
whack, whack - BLAM!

Numb fingers. Time to buy a press....

 

[Jim Watson]

I have popped two on the press. One on the Dillon S1050, I don't know what happened there, it will crush a primer without the impact normally required to fire. The other was on my old CH Autochamp which sheared a primer because the tricksy straight line travel came up short.

 

[Dudedog]

When the primer wouldn’t go in smoothly I just chamfered the pocket a little and they go in just fine.

Sounds like a case with a crimp was the cause of you problem, suspected that might have been the caue.

I asked the OP where his jolt came from. It seems obvious it came from a crimped pocket that he built up force against and then moved/bent/swaged/slipped enough to let the primer and seating arm suddenly jump forward - like a dull knife finally pushed hard enough to get through the food. Like a suddenly moving knife plowing into the cook’s left hand, the primer and seating arm, now moving fast, suddenly ran into the bottom of the pocket or another snag. There’s the jolt, and thence the pop.

This is probably why.

Crimped primer pockets are a PITA, only good thing about them is you can be fairly sure the case is once fired....

 

[jmorris]

Swage or ream crimped primer pockets.

Don’t force anything, ever, if it’s not going to go all your going to do is destroy something.

Be smooth, no jerky movements. Before the internet and forums existed, it had heard of people lighting off primers seating them I couldn’t believe it because in my learning curve I had seated some sideways and otherwise mangled them without ignition. I went so far as smushing some completely flat in a bench vise and they didn’t go off.

Fast forward 30 years and I was over at a friends house helping him to get a press running smoothly and he went to another press to load ammunition for a match we were going out of town to attend. Already frustrated before I got there, I could tell he wasn’t in the right frame of mind (my opinion) to be performing the task. A few minutes of “your gonna do what I want” and he lit off an entire tube.

Don’t want it to happen again? Do what you did for the first decade and don’t repeat what you did to light that one off.

 

[Cemetery21]

They will take a lot of abuse, just not from a certain angle. I hit this one twice with a firing pin before I got it in good enough light to see the issue.
And, no kaboomed primers since I started in the early 70s (knock on wood).