MISFIRE MYSTERY

[8x68s]

anyone experienced a similar misfire?...
my reload (powder and bullets) with pre-primered (someone else's work) 7mm Mag cases. Three "no fires" out of 10 attempted. Solid firing pin strike, twice, still "no fire". No bullet movement apparent, pulled the bullets and found all powder burned, carbon residue left, empty case. Checked powder ignition separately with a match and small quantity, showed no problem. What happened here?

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[jordanka16]

Sounds like maybe something leaked into those cases? It could have caused the powder to just smolder and turn to carbon instead of burn like it was supposed to. Did the other 7 go off fine? Or did they seem off as well?

I wonder what whoever sized and primed those cases used for lube and how careful they were with it.

 

[8x68s]

other 7 went bang just fine. Your other point is the same as I was thinking but I can't confirm by looking at the other unused cases I have in stock. There is a blue-ish coloring around the primer pockets and I'm wondering if "whoever" tried to seal the primers and got too much on them?? Rather than load any more, I thought I would fire the primed cases and start over from scratch.
Thanks for the input, sir...

 

[Caveman Jim]

From what I have read, the case lube should be cleaned before loaded. As stated above, this may well be the culprit...
My limited experience since delving into reloading is to follow all the rules all the time...... but the laws of relativity certainly do not rule out "Brain Pharts"....

 

[jordanka16]

I wouldn't think that faulty primers would cause that, they should either light the powder or not light it, not make it smolder. Is the primer sealant puddled in the bottom of the cases? It sounds like powder contamination to me, either way, getting rid of those primers and then cleaning the cases should solve it, good luck!

 

[8x68s]

Primer sealer is not puddled or generally excessive. Cases are clean inside, no evidence of lube. Caveman's advice on following "the rules" is certainly pertinent... don't let someone else into your reloading stream of assembly. Having primed cases from elsewhere provides the possibility for trouble, even if unexplainable. thanks for the input, gentlemen...

 

[Certaindeaf]

Wow, that's something. It sounds like the primer didn't have enough brisance to properly ignite the charge but instead had just enough to cause it to smolder/burn. Count yourself lucky on a few fronts.
good idea to pop them primers and do over from scratch

 

[Xaevian]

Primers are pretty sensitive to moisture, and I can see pre primed cases being part of the issue as the history of them would be unknown to you. They are also susceptible to crushing if seated too aggressively. It does sound like powder contamination could also be an issue, but again the history would be an unknown. Out of my last 1000 CCI primers, I have never had one misfire, but I was involved with the entire reloading process and I don't use primer sealant.

 

[Crohnos01]

Strange. I have had primer failures, but the powder remained intact. Sounds like the primer ignited the powder, but the powder didn't burn effectively to cause pressure inside the case? Any sign of gas leakage around the neck of the case or the primer pocket?

 

[v0lcom13sn0w]

lube from sizing die


i just had a stint where i wasnt cleaning primer pockets and primers were getting "seated"with my firing pin and would go off on a second attempt

 

[Crohnos01]

Maybe...silly me... I always applied the lube to the OUTSIDE of the case

 

[Certaindeaf]

.Any sign of gas leakage around the neck of the case or the primer pocket?

Uereka.
OP, did you size that primed brass? it would be understandable if you didn't. Did the case mouth grip the bullets firmly? Check the rest of your loaded rounds and or brass with a micrometer to find out their specs.
It would explain weak combustion.. lots of powders, especially magnum/slow powders need a physically strong enclosed environment to build up pressure for proper ignition/burn.

 

[RVTECH]

From what I have read, the case lube should be cleaned before loaded.

Yep - lube, size, trim, chamfer THEN clean/tumble etc. before loading.

 

[ageingstudent]

lube from sizing die


i just had a stint where i wasnt cleaning primer pockets and primers were getting "seated"with my firing pin and would go off on a second attempt

I put too much oil on my auto-drum mechanism and riser/expander die and neglected to remove the excess. I had 2 squibs in that batch I'm fairly confident I know where the excess oil went. Both loads had a sooty half burnt powder stuck to the back of the bullet and inside the cases. Lesson learned.

 

[AMProducts]

Ok... Something isn't making sense here

If the primer went off, and "burned" the powder, even if it didn't have good enough ignition characteristics, generally once the powder gets burning in a confined space, you get a bang. This can be a hang-fire.

Now, I have seen situations where some heavy rifle powders (like the kind you load in 7mm rem mag) will "flash over" usually this leaves the powder looking kinda yellow.

I don't know why, but I'm getting a sense of deja vu here.