Ever had a primer fail?

[Brad]

I blew a primer from a case once. Once.
Learned a bunch about heat and ball powder. Load was about a max charge of H450 ina 270 win. Looked after ejecting case and saw a primer. What? Looked at case and said "oh shit". Stopped shooting. It was 90° plus and the barrel was pretty hot.
Good thing it didnt do any more than that as it was my mom shooting in prep of her forst deer season. She used a different load.

Learned a lesson that day. We got lucky. I don't press my luck anymore.

 

[SierraHunter]

I've stretched primer pockets before. I wont deny that I like to load hot, with jacketed. I didn't think 20gn would be too hot hitherto a cast bullet, since the Sierra manual goes to about 25 with the same weight bullet in jacketed, but I guess I was wrong.

The thing that still gets me, and I guess what made me think it was not too hot of a load was the fact that the primer pocket did not stretch, even though the primer blew out.

 

[Ian]

It's a half load unless you get SEE, which is what Rick was trying to explain to you.

Did the data you referenced get pressure-tested with powder-coated bullets, magnum primer, and two-dozen fired, multi-annealed, necked-up-three-calibers machine gun brass with probably no neck tension and reamed instead of swaged primer crimps?

What I really want to know is why you haven't bothered to check any of the things that so far have been suggested, such as elliptical or ovoid primer pockets, pitted bolt face, firing pin hole, etc. If you want to solve this instead of yammer on about it for pages, get going.

 

[SierraHunter]

It's a half load unless you get SEE, which is what Rick was trying to explain to you.

Did the data you referenced get pressure-tested with powder-coated bullets, magnum primer, and two-dozen fired, multi-annealed, necked-up-three-calibers machine gun brass with probably no neck tension and reamed instead of swaged primer crimps?

What I really want to know is why you haven't bothered to check any of the things that so far have been suggested, such as elliptical or ovoid primer pockets, pitted bolt face, firing pin hole, etc. If you want to solve this instead of yammer on about it for pages, get going.

Yes sir. I'll go get the bolt can give it a look over. It's very probable that the bolt has pitting since the action was originally found in the bottom of a boat. It has been a 6x45 for close to 20 years though.

 

[Tom]

Rick, you may have hit on his problem, being he used 450s with 4895. It shouldn't be deteriorated powder, I gave him that jug of imr 4895 recently, and it still appears to be in good shape. His load doesn't seem hot, and should be 75 to 80 percent full, so I wouldn't think it would be SEE.

 

[KHornet]

Obviously something went wrong. When that happens to me I look in a mirror
first, to go thru the procedure and analyze it first and then me. I can usually figure
it out. Doesn't sound like a primer issue to me however!

 

[SierraHunter]

I just went and got the rifle and the case from the house. While I was there, I dug around in dad's milk crates full of papers and found a file on this rifle from when he had it. He went up to 23.5gn of H4895 with this bullet, but he was using standard lube. I also noticed that he used SRM primers in all loads using 4895.

I'm guessing I must have over annealed the cases, or maybe the PC bullets were just too fat for this gun. Maybe a combination of both of them. I'm still puzzled as to why the primer pocket did not stretch, but I may never figure that out.

 

[Ian]

75 to 80 percent full, so I wouldn't think it would be SEE.

You don't understand either. Read what Rick and I wrote. Think bore obstruction.

 

[Rick]

I didn't say the 4895 was bad, he posted in another thread that uses degraded 4198 without concern. A 450 will easily move the bullet out of the case and jam it in the rifling. At that point you have an obstructed bore and then the powder ignites, pressure builds way past normal, the next step is digging a primer out of your face being thankful it's not in an eye.

 

[SierraHunter]

You don't understand either. Read what Rick and I wrote. Think bore obstruction.

So should I be checking the gun for a bulged chamber/bore?

 

[Tom]

Sorry, I'm trying, Ian. If I understand correctly, you two are saying the 450 pushed the bullet into the bore before full ignition. I think that may have been the culprit. Looking at Daniel's pic of the brass,there appears to be a bright ring at the head.

 

[SierraHunter]

I didn't say the 4895 was bad, he posted in another thread that uses degraded 4198 without concern. A 450 will easily move the bullet out of the case and jam it in the rifling. At that point you have an obstructed bore and then the powder ignites, pressure builds way past normal, the next step is digging a primer out of your face being thankful it's not in an eye.

I don't recall naming any powders. I've actually only used a couple of rusty powders, and they were very slow rifle powders.

I can see where the primer moving the bullet forward could cause a problem. That's probably what happened since I was using same what freshly annealed cases and lightly neck sizing.

 

[9.3X62AL]

Gas got into the action in some way or fashion. Pitted bolt face and/or over-sized firing pin hole in bolt face occur to me as first possible sources of the anomaly. The load/powder weight seems reasonable, but the case lost gas containment--which is its primary duty, when assisted by a sound action and bolt. Confirm that last condition before doing any further firing of this rifle. Not trying to be hyper-didactic here, but unmatched fuel and spark plug (4895 x CCI 450) and much-used brass are safety cacaphonies, and if the bolt face or action are deficient you are playing in a concert hall of pending disaster. I know that components are often difficult to locate and expensive when found, but these serial improvisations don't always cancel each other out--and in this particular incident cascaded geometrically. I am glad your eyesight was not affected or destroyed.

Rick's SEE scenario makes a lot of empirical sense, and may be the sourcing of the over-pressure situation that caused the gas escape/containment failure, likely via the primer cup at the firing pin indentation point. Gas propagation essentially blew the primer cup metal through the bolt's firing pin gallery and into the action, avulsing the extractor and overcoming the floorplate's spring detent. All things have their limit, and the primer cup is the weakest link in the cartridge case containment chain. Under normal pressure circumstances, the pressure pulse strength and its dwell duration is contained by the primer cup metal supported by bolt face and firing pin tip end under its spring tension. Exceed max specs, and bad things happen.

 

[Tom]

Maybe you didn't name the powder, I'm mixing our online conversations with our phone conversations, I guess. I think Rick nailed it.

 

[SierraHunter]

I've never really thought about having too much spark before. But I guess it could cause a issue.

I don't usually wear safety glasses when shooting, but had them on today for whatever reason. I don't think I'll do any more shooting without then after this.

 

[SierraHunter]

Maybe you didn't name the powder, I'm mixing our online conversations with our phone conversations, I guess. I think Rick nailed it.

That comment was directed towards Rick about the deteriorating powder. The powder used in this load was the powder that I got from you.

 

[Tom]

The safety glasses thing might be worth the cost of admission alone. Now, if I'd only heed my own words....

 

[SierraHunter]

Yep. I'm gonna pick up a few pairs to keep in my trucks as well.

 

[Rick]

I've never really thought about having too much spark before. But I guess it could cause a issue.

I don't usually wear safety glasses when shooting, but had them on today for whatever reason. I don't think I'll do any more shooting without then after this.

Take one of your old worn out cases that could well have been over annealed and load a 450, NO powder at all and seat a bullet. Fire that and see how much effort is required to get the bullet out of the bore. Add to that it's possible that "some" of the powder may have ignited jamming the bullet deeper into the bore before the main charge ignited.

Did the bolt remain closed during this? You said the floor plate blew open, how about the bolt, you never mentioned that.
.

 

[SierraHunter]

The bolt did stay closed. It also opened easy when I went to open the bolt, although with the extractor off it wasn't grabbing anything.

I never paid much attention, but I guess this rifle had a sako style extractor. I found the main part, but not the spring and detent.