Primer Seating Causes Firing

[Rich/WIS]

Don't use a progressive but had two Win LP go off when priming on the upstroke with my old Lyman Spartan.

[JoeJames]

I use either Winchester or CCI primers, and a very old Lee Auto Prime. I noticed in the fairly recent Lee Manual that they recommend limiting the number of Winchester primers in the tray depending on whether they are large or small primers, and flat out discourage the use of Federal Primers in either version of the Auto Prime. CCI's are just fine in any quantity.

[bedbugbilly]

John - thanks for taking the time to answer my questions - I greatly appreciate it. And please realize I was not thinking that you had mixed a small primer case with a larger primer case - I have just always been curious as to the possibility of this happening and the results on a Dillon or similar press.

I'm pretty "low tech" and I prime with a hand primer - I don't reload the quantity that some of you do, especially if you are shooting competition, etc. At one time, I was going to reload 45 ACP as i was going to switch from 9mm to 45 for carry. I got dies, molds, range brass, etc. and then changed my mind and stuck with the 9mm for carry - so I never bought pistol and ended up giving the 45 ACP things to a friend whose Dad wanted to reload 45 ACP. I do relod a number od different pistol cartridges as well as bottleneck rifle cartridges. Mostly, I have always tried to buy 1 X fired range brass as it works fine for what I'm doing.

Not that it has anything to do with what happened to you, but I did learn a lesson on "rage brass" one time. I bought about 3,500 9mm casings from a guy on here - he claimed it was 1 X fired. It was dirt cheap so I got it and figured it would be a good supply to have on hand. It had been tumbled and deprived so that was also a plus - at least in my mind. It was s hodge lodge of bead stamps. I sat down to load a couple hundred and started off hand-priming and talk about a PIA! As I inspected each casing, I tossed some as I don't know what they had been fired in, but the head stamps on some were distorted as if they had been loaded hot or shot in a pistol with headspace issues. I got a good rhythm going on the priming and then - what the heck? I couldn't get the primer started into the pocket. I checked the head stamp - not military - O.K. I'll just toss it. The further I got into the batch, the more issues I had with seating the primer in some of the cases - and it wasn't just one head stamp - it was numerous beadstamps. I was using CCI primers and I have never had an issue with them. I switched to another hand primer I had - same issue -- about every 8th or 9th casing the primer pocket was an issue. At the time, I remember thinking about what would have happened if they were being primed on a automatic press of some type. Long story short - I didn't have a primer pocket swaged at the time and it was such a PIA the I ended up scrapping out all of the casings - it was just too time consuming to fool with. I have never had another issue with 9mm range brass that i he purchased and I never did figure out what the issue was with so many mixed head stamps and difficulty in seating primers - and the same hand primers and batch of CCI primers seated perfectly in other batches oof range brass.

Just glad that you or the press weren't hurt! It may be something that know for sure what caused it. Like already mentioned - a good reminder to all of us to wear safety glasses. An interesting thread and interesting responses - and also a good reminder about checking each casing - I was reminded of that with my own experience with the .223 casing and the fragment of a SS tumbling pin.

[Burnt Fingers]

I sort LPP and SPP 45 brass on my 650. For me it's easy to tell when a SPP gets to the priming stage. I sort crimped 9mm on the other 650, again it's easy for me to tell when one gets to the priming stage.

My buddy for some reason can't tell the difference on 9mm. His solution was to hammer the handle back. I stopped that real quick.

I've had a few sideways primers, but I've never had one go off.

[FLINTNFIRE]

Had one winchester go off in a rcbs hand priming unit , it can and does happen , as to small primer 45acp it is easy to tell when you go to prime on my square deal b , it is one reason I soldered a piece of wire to the shell locator buttons , have run into 9mm and 40 that were not military headstamps that had crimped primer pockets , mixed range brass or once fired can be a crap shoot as to quality and sellers honesty .

[JoeJames]

Cousin gave me several boxes of white box Federal 556 and they all had the crimped primer pockets.

[dannyd]

I have often wondered - since 45 ACP brass comes in both small and large primer - as careful as a person may be - if loading range brass - what happens on a press such as a Dillon where you are automatically priming in the cycle and are using large primer brass but a small primer casing somehow gets mixed in? Is that enough to set a primer off or does it just crush it?[/QUOTE]


Nothing happens; if your loading large primers and get a small primer case you can feel it not going in and stop. If you loading small primers and get a large case same thing you can tell by the feel it as no primer or powder trail after it leaves that station.

[ioon44]

45 ACP brass comes in both small and large primer , when I started dealing with this I developed the habit of looking at the case head before placing it in my 550 shell holder and have found .380 & .38 super when loading 9 mm.

Reloading requires one's full attention.

[cp1969]

I have three ways of priming--Dillon 550B, RCBS Jr., and Lee hand tool. I don't know why but the Dillon does the worst job of the three. It seems like it takes far too much pressure for a compound press and the primers' bases are sometimes noticeably wrinkled. Never had one go off, though.

[jakharath]

I have three ways of priming--Dillon 550B, RCBS Jr., and Lee hand tool. I don't know why but the Dillon does the worst job of the three. It seems like it takes far too much pressure for a compound press and the primers' bases are sometimes noticeably wrinkled. Never had one go off, though.

Howdy, you may need to replace the primer cup and rod on your 550.

[Tatume]

It seems like it takes far too much pressure for a compound press and the primers' bases are sometimes noticeably wrinkled.

I suggest you check the primer slide adjustment. If it is off the misalignment can cause the symptoms you describe. While you're at it, clean the mechanism too. When they are adjusted correctly and clean the Dillon 550 machines do a great job of priming.

[John Boy]

Any primer will ignite if it is struck Hard and Fast. So slow down jerking and hammering the press arm when reloading.

[Tatume]

Any primer will ignite if it is struck Hard and Fast. So slow down jerking and hammering the press arm when reloading.

There is no evidence of this. The OP asked a legitimate question to which he received thoughtful responses, mostly.

[Hossfly]

Never used a 550 but do have a 650 for last 5 years, my mentor instructed me to always limp wrist the priming stroke and if there is too much resistance, stop and pull that one out. Sure nough last week while Running 45’s found about 20 SP in bag of 100 out of 1500 i purchased locally from store getting out of reloading supply business. What a PITA that was, but it avoided the problems i think.

[DougGuy]

I always hand prime, there is just too much adjusting and inconsistencies to prime on the press. If it ain't one thing, it's another that inevitably causes a problem. I don't load 1k rounds at a time anymore so hand priming works for the amount of ammo I need, and if it is hunting ammo, I do everything by hand single stage, weigh each charge, I don't want no surprises when I am aiming at hide.

I only keep WLP for all pistol ammo, and Federal for rifle so that simplifies things and eliminates variables. Variables are what gets you, those are not blatant mistakes, but jusssssssssst enough to make you go Hmmmmmmm when something doesn't go right.

[1hole]

Primers normally don't denotate with a slow compression. I have tested this several times by squeezing them flat in a machine vise.

Ditto. I've slowly crushed primers into a small flat mass in a 70 pound shop vise; I crushed them side to side and top to bottom but with no fireworks. And I've de-capped quite a few live GI pull-downs with Lee's tuff Universal Decapper Die with no events. Been doing this a long time and the only way I've seen a primer go off was from heat or impact.

I have to wonder how vigorously that Dillon's handle was being manipulated. ??

[Tatume]

Ditto. I've slowly crushed primers into a small flat mass in a 70 pound shop vise; I crushed them side to side and top to bottom but with no fireworks. And I've de-capped quite a few live GI pull-downs with Lee's tuff Universal Decapper Die with no events. Been doing this a long time and the only way I've seen a primer go off was from heat or impact. I have to wonder how vigorously that Dillon's handle was being manipulated?

I was very surprised when a primer detonated upon being run over by a hard rubber wheel on a dolly. I don't know if I could ever reproduce the event, but it happened at least once.

Just because you haven't seen it happen does not mean it hasn't happened.

[1hole]

Just because you haven't seen it happen does not mean it hasn't happened.

You are quite correct and neither of us has suggested otherwise.

[cp1969]

Ditto. I've slowly crushed primers into a small flat mass in a 70 pound shop vise; I crushed them side to side and top to bottom but with no fireworks. And I've de-capped quite a few live GI pull-downs with Lee's tuff Universal Decapper Die with no events. Been doing this a long time and the only way I've seen a primer go off was from heat or impact.

I have to wonder how vigorously that Dillon's handle was being manipulated. ??

If that question is directed at me and my Dillon, it was manipulated just vigorously enough to not have a high primer and no more. I even tried adding a step to clean the primer pocket but that didn't make any difference.

[Geezer in NH]

OP having prior problems with Dillon and priming.

http://castboolits.gunloads.com/show...B-Primer-Setup