I had 4 primers misfire yesterday while testing some 404 Jeffery loads. They were CCI #250 in fresh Norma brass. Total rounds fired 33

I had 4 occurrences:
1. Initial "click" - waited 10 seconds (in case of a hangfire) - rechambered -worked
2. Ditto as above
3. Ditto as above, but it took a second chambering
4. Tried multiple times, not luck

All of the primers had sufficient indentation from the firing pin.

I've had no issues with the same lot of primers in my 458 Win Mag and have never had a misfire on any of the CCI #200 primers I use.

After reading up on this topic, my conclusion is: that the primers were seated to high and the initial strike pushed them down and the 2nd or 3rd strike ignited them. And on the 4th one, it was seated way high and multiple strikes damaged the primer so it never fired. None of these primers had light indentations from the firing pin, all were normal.

Do this conclusion make sense?

Is there ANY chance they were seated too deep?

It makes sense.

Seating too deeply is very rare since the primer pocket would have to have been cut too deeply. Are you reaming primer pockets?

I prime with a hand priming tool just to feel the positive stop when I seat primers.

More than likely that the primers weren't seated deeply enough. I had that problem so I switched to a hand priming tool to make sure they were fully seated. Problem solved.

quote:

More than likely that the primers weren't seated deeply enough. I had that problem so I switched to a hand priming tool to make sure they were fully seated. Problem solved.

I've never had an issue after I went to a hand primer.

Can't see how they could be seated too deep unless there was an issue with the brass. Also if too deep I would think you would see a lighter strike.

Waiting for a possible hangfire to happen is nerve-racking with a .22 Hornet. It must be agony with a .404 Jeff!

Sometimes the imprint of the firing pin on the primer can fool you. I like and use CCI primers in many loads, but their cups have a reputation for hardness. I have one rifle which simply refuses to make about every third CCI SR primer go off. Swap them out for any other brand of primer and see what your results are (you don't have to waste expensive powder and bullets, just prime some brass with some CCI 250's and some other LR primer and go out in the garage to "pop" them to see how others compare to the CCI's in your rifle.

Thanks for all the help. I like Stonecreek's advice - saves time!

Not so much as "seated too deep" but maybe not deep enough. If there is a gap between the back of the primer and the primer cup, the firing pin can drive the primer into the cup,still making a dent,but not setting it off. I have done it a few times over the years.

There is also the possibility of the new brass being undersize creating a headspace issue

Be sure to check firing pin protrusion and the mainspring.
What action are you using?
The M70 has a short firing pin fall that sometimes does not get the job done.

quote:

Originally posted by SR4759:
Be sure to check firing pin protrusion and the mainspring.
What action are you using?
The M70 has a short firing pin fall that sometimes does not get the job done.

1917 Enfield. Yes, I need to measure the protrusion. I have a special gauge for that. Spring is new I believe. But the indentations were all solid.

If you have a look at the underside a Boxer primer you can see the legs (usually three) of the anvil protruding slightly from the bottom edge of the primer. The anvil legs must seat firmly in the primer pocket in the case head with the primer cup itself seated firmly down onto the anvil slightly crushing the priming compound between the two.

I have never used a hand primer but do all my priming on my press and seat the primers firmly. I have read somewhere that the primer compound is sensitized as the primer is seated firmly onto the anvil either of Boxer primers or Berdan primers which have an integral anvil in the case head. I load both types of primers.

Does your action still have the original cocking system? (cock on closing)

I ask because some Enfield actions have been fitted with 'cheap and nasty' cock on opening systems which give a very short firing pin fall and suspect ignition.

quote:

Originally posted by redrover:
Does your action still have the original cocking system? (cock on closing)

I ask because some Enfield actions have been fitted with 'cheap and nasty' cock on opening systems which give a very short firing pin fall and suspect ignition.

It's cock on opening. I had a competent gunsmith do the conversion that does Enfields, but will check the firing pin protrusion.

Many cock on opening conversions (wrongly) use the original cocking cam and that greatly reduces the firing pin fall distance; try some other (softer) brand of primer or go back to cock on closing; like they were designed for and like works reliably every time. I never understood the American dislike for cock on closing; one thing the British did right.

quote:

Originally posted by dpcd:
Many cock on opening conversions (wrongly) use the original cocking cam and that greatly reduces the firing pin fall distance; try some other (softer) brand of primer or go back to cock on closing; like they were designed for and like works reliably every time. I never understood the American dislike for cock on closing; one thing the British did right.

When you saw fall distance, you are referring the distance the firing pin travels from cocked to fired? Correct? Not the length of the protrusion on the pin relative to the bolt face.

Good news: firing protrusion .065"

Bad news: travel distance about .22-.23" (couldn't measure as accurately).

I'm not sure which spring is in there, but I ordered a Timney and will see if that is strong that what's in there.

Yep; fall distance; in your case, you have the worst situation; short fall and probable weak spring. If you have a weak, original spring, you need a long fall for it to work. A strong spring will make it work, but will also make it hard to open. Solution; revert back to cock on closing.
The right way to do it, if one must, is to weld the cocking cam on the bolt, longer. It is just not a necessary thing; I do not mind cock on closing, in case you can't tell.

I tried to keep the cock on closing, just could not get used to it; but if it becomes a beast to open with a heavier spring, it might be the right answer - other than relocating the cocking cam.

Timney spring worked fine. I had to remove 1 coil to get it to fit. It's stronger than what was on there, but not bad at all.