Split primers

[fatelk]

Anyone ever have a certain brand or lot of primers that split or ruptured without an apparent overload?

I recently changed primers on some .44 mag loads, backed off a little to work up. I was surprised to see an occasional primer leak, split from the firing pin indent outward. No other sign of excess pressure, velocity across the chronograph was fine, extraction was fine. I switched back to the Winchester LP from the Fed 155 and all is well again. The specific load is 22.4 gr. H110 under a 429244; not a weak load by any means, but still a little under book max.

Yes, I know that minor changes in primers, brass, individual gun, etc., can and will all affect pressure. I'm curious if anyone has ever seen this kind of thing before: whether it's a soft primer thing, or it really is an over pressure problem that I'm not quite understanding.

[Scharfschuetze]

Not a totally uncommen event. I've had the issue a couple of tmes, most recently with Remington SR primers. Sometimes the crack will allow enough hot gas by to divit your bolt face.

[tazman]

I had that happen with some Remington sp primers a couple of years ago.

[Ballistics in Scotland]

When it isn't happening, do you get a small puncture right in the middle of the indentation? That would be caused by excessive firing-pin protrusion, and can be cured by very slight stoning of the firing-pin tip, to make it a little more pumpkin shaped than spherical.

Pressure has almost nothing to do with that kind of puncturing. I have had it happen on a previously unfired .38 S&W Webley. I haven't seen a radial split developing from that, but can imagine that it might. I don't think it can be anything to do with excessive pressure, which would show up in a split or cratering around the edge of the indentation.

[Bent Ramrod]

I had some RWS primers (maybe 1960's vintage; came in trays of 250) that would do that sometimes. Maybe the metal used in the cups for that lot of primers was overly work-hardened or under-annealed.

Other primers in the same shells with the same loads in the same gun worked normally.

[Ken in Iowa]

I really wish people would be more specific about which primer they are using. Many manufacturers have 2, 3 or even 4 types in any given size. /rant mode off.

[jsizemore]

I'd load some 44 special power loads and try them in another gun (45acp?). Should tell you if it's the gun or primer. It would be hard for me to dump a 1000 primers but we have to be safe.

[jsizemore]

I really wish people would be more specific about which primer they are using. Many manufacturers have 2, 3 or even 4 types in any given size. /rant mode off.

I can see why Mr elk didn't name a specific primer to curtail the mania that may ensue.

[Ballistics in Scotland]

I would shrewdly surmise that he was using Federal 155, and other people's experiences were incidental enough not to really require much in the way of detail. It is a valid point with other threads where people report a primer problem, though.

[fatelk]

Yes, the primers in question are Federal 155. They are some older ones I've had around for a few years (or more). I wondered if it could be a firing pin issue (as Ballistics suggests), so I did take the bolt apart and check out the firing pin closely. I think I'll take it apart again and try what you suggest.

The same loads with the same primers works fine in my S&W 629, and the same load with Winchester primers works fine in the rifle. I wonder if it could be a combination of brittle primers and a firing pin a little out of spec. I don't have many of the Federal primers so I'll just use them up in something else, and continue with the Winchester primers.

[tazman]

On the Remington primers I had problems with, They would blow out at the edge and sometimes split to the center. Others would get a hole in the firing pin indent. They were not consistent in where the hole would be.
I swapped out the primers for a different lot number and the problem disappeared. Fortunately this didn't happen with 38 special loads. Only with 9mm.
I finished using them up in 38 special loads.

[243winxb]

Photo of the split primers? Thank you for the reply below.

[fatelk]

Sorry, that brass has already been sized and the primers in question are long gone. It was always a crack radiating from the firing pin dent outwards.