Tell me what would cause a rifle to deeply dent a primer and it not cause it to fire. UPDATED - Page 1

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[ARCHIVED THREAD] - Tell me what would cause a rifle to deeply dent a primer and it not cause it to fire. UPDATED

Posted: 11/5/2018 12:34:24 PM EDT

Took a rifle in trade that has this issue, using brand new bench rest CCI primers it will deeply dent the primer, but the round will not ignite. Sometimes it takes 2-3 tries before it may go off. Could this be an issue with the striker velocity as in the striker spring is worn and weak?

Read the solution down the page, the misfires are not caused by primer seating or bad primers. AeroE

Posted: 11/5/2018 1:05:05 PM EDT

[#1]

Quoted:
Took a rifle in trade that has this issue, using brand new bench rest CCI primers it will deeply dent the primer, but the round will not ignite. Sometimes it takes 2-3 tries before it may go off. Could this be an issue with the striker velocity as in the striker spring is worn and weak?

View Quote

Primer not fully seated?

And sometimes the primer pellet splits and may not ever ignite.

Posted: 11/5/2018 3:42:47 PM EDT

[#2]

Bad primer(s).

Posted: 11/5/2018 8:59:59 PM EDT

[#3]

Quote History

Quoted:

Primer not fully seated?

And sometimes the primer pellet splits and may not ever ignite.

View Quote

Primer fully seated flush with the case. Virgin Lapua brass.

Posted: 11/5/2018 10:49:08 PM EDT

[#4]

Could be a bad primer. I've had a few. What rifle?

Posted: 11/5/2018 11:07:26 PM EDT

[#5]

Trigger over travel set to tight, and causes binding on the striker as it moving forward.

Could be wear to the FP tip with not enough protrusion, could be weak FP spring, or could be the grease used in the striker that is slowing down the FP as well.

Posted: 11/5/2018 11:15:48 PM EDT

[#6]

Chamber headspace is too deep.

You need to create a false shoulder on the brass with an expander mandrel, then neck it back down to 6mm, leaving a small section with a larger diameter.

Then you can fire form your brass to that gun and only bump the shoulder back .001-.002" for the next firing.

Posted: 11/7/2018 7:33:28 AM EDT

[#7]

What type/model of rifle is this?

Posted: 11/7/2018 10:12:11 AM EDT

[#8]

Quote History

Quoted:
What type/model of rifle is this?

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A custom bolt gun on a Stiller action in 6mm Norma BR.

Posted: 11/10/2018 1:33:46 PM EDT

[#9]

Quote History

Quoted:
Primer fully seated flush with the case. Virgin Lapua brass.

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Quote History

Quoted:

Quoted:

Primer not fully seated?

And sometimes the primer pellet splits and may not ever ignite.

Primer fully seated flush with the case. Virgin Lapua brass.

The problem is that even flush can still be not at the bottom of the primer pocket.

Most primer pockets are slightly deeper (by a few thousandths of an inch) than the height of the primer.

The primer should be very slightly BELOW the case head.

Posted: 11/10/2018 3:02:34 PM EDT

[#10]

Quote History

Quoted:

The problem is that even flush can still be not at the bottom of the primer pocket.

Most primer pockets are slightly deeper (by a few thousandths of an inch) than the height of the primer.

The primer should be very slightly BELOW the case head.

View Quote

Yep, primer pockets are designed so the face of the primer is slightly recessed before the face of the back side of case.
So high sitting primer (not seated to the bottom of primer pocket) can end up with the primer compound disk and below anvil being shoved down in the primer to the bottom of the channel (anvil now in the wider part of the pocket, and not still in the primer cup containment), and not enough primer compound disc impact force between the cup and top of anvil to set the primer off with the limited amount of FP protrusion available.

Posted: 11/18/2018 9:27:12 PM EDT

[#11]

Headspace

Posted: 11/18/2018 9:32:38 PM EDT

[#12]

Where did OP go?

@P08

Posted: 11/18/2018 9:37:43 PM EDT

[#13]

I'm here, just have not had time to mess with it. I spoke with a gunsmith and he thinks trying a striker spring would be a first step. So gonna give that a try.

Posted: 11/19/2018 4:08:41 AM EDT

[#14]

I got a thousand primer box about 4 weeks ago and was getting no fire on the majority of them, like 9 out of 10 would not fire. The manufacture sent me an overnight tag to return to the factory and they did some testing and the majority of a 1000 primer pack was no good. They send me two 1000 round packs to replace them and have had no problem since, but they had a batch of bad primers.

Posted: 11/27/2018 9:15:26 PM EDT

[#15]

Ok, finally had time to mess with it again. It is a Shilen DGA action and I discovered through an internet search that it has a firing pin that screws into the cocking piece. It was not lock tighted and the pin apparently had backed off just enough that it would not fire. So now I need to find the correct firing pin protrusion depth set it and lock tight the pin.

Posted: 11/27/2018 9:22:01 PM EDT

[#16]

Quote History

Quoted:
Ok, finally had time to mess with it again. It is a Shilen DGA action and I discovered through an internet search that it has a firing pin that screws into the cocking piece. It was not lock tighted and the pin apparently had backed off just enough that it would not fire. So now I need to find the correct firing pin protrusion depth set it and lock tight the pin.

View Quote

That will do it. I did that to my Mark V once.

Should be about .055-.060" protrusion.

Posted: 11/29/2018 12:12:43 PM EDT

[#17]

Quote History

Quoted:

That will do it. I did that to my Mark V once.

Should be about .055-.060" protrusion.

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Set the protrusion to about .60 and locked it down. The primer that it only dented before now fired.
Thanks for the info.

Posted: 12/8/2018 7:47:27 PM EDT

[#18]

Quote History

Quoted:
Chamber headspace is too deep.

You need to create a false shoulder on the brass with an expander mandrel, then neck it back down to 6mm, leaving a small section with a larger diameter.

Then you can fire form your brass to that gun and only bump the shoulder back .001-.002" for the next firing.

View Quote

At first I considered the same thing but this would result in light primer strikes, not deep strikes.

I'm at a bit of a loss to explain how the firing pin could cause a deep hit on a primer without setting it off. Doesn't make sense.

Posted: 12/8/2018 10:56:11 PM EDT

[#19]

Quote History

Quoted:
At first I considered the same thing but this would result in light primer strikes, not deep strikes.

I'm at a bit of a loss to explain how the firing pin could cause a deep hit on a primer without setting it off. Doesn't make sense.

View Quote

If it is not seated to the bottom of the primer pocket it will be deep because it is higher than normal and NOT go off because the energy is wasted pushing it into the pocket.

Posted: 12/9/2018 12:50:01 AM EDT

[#20]

Quote History

Quoted:
If it is not seated to the bottom of the primer pocket it will be deep because it is higher than normal and NOT go off because the energy is wasted pushing it into the pocket.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
At first I considered the same thing but this would result in light primer strikes, not deep strikes.

I'm at a bit of a loss to explain how the firing pin could cause a deep hit on a primer without setting it off. Doesn't make sense.

If it is not seated to the bottom of the primer pocket it will be deep because it is higher than normal and NOT go off because the energy is wasted pushing it into the pocket.

Primers were seated in fully. I can only think that there was enough inertia to dent the primer, but not enough pin protrusion to actually hit the anvil?

[ARCHIVED THREAD] - Tell me what would cause a rifle to deeply dent a primer and it not cause it to fire. UPDATED

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