Failure to fire

[MikeRu]

I had a new factory Bergara with FTFs, cleaning out the factory lube inside the bolt fixed the issue. And you’re at 10F. Someone mentioned this above.

 

[Webster]

Rifle-
Brand new.
6mm Creedmoor. Defiance anti-x with PVA carbon prefit, trigger tech rough diamond.

Conditions:
10*F ammo left out (under cover) for an hour before firing.

What I’ve checked:
1.Recheck headspace with go/ no go gauge. All good.
2.same lot of primers in a different rifle fired all 10 rounds no issue.

Factory ammo:
Ran all 12 rounds that I fired through it flawlessly (sig elite series -100 gr).

Hand load:
7 out of 16 rounds did not fire.
Using CCI200, virgin Peterson brass (did not run through a sizer), H4350 (1.0gr under book max) ,95 tmk. COAL 2.770.

Question:
I’m assuming it’s something with the hand load. I’d normally suspect the primer but no issues in another rifle. Next thought was the firing pin/spring but it ran all the factory ammo just fine. Not sure what’s going on?

Picture:
Top of the pic- factory sig.
Next rows are all my hand loads. The ones that stick up higher are the FTF rounds.

Ideas?

Edit to add info after a page of discussion:
1. Yes there is powder in all the cases
2. Datum to case head is the same on both fired vs no fired
3. The rounds that did fire had the primers seated flush.
4. Primers set from .0045-.014 below flush all FTF. I believe Sammi spec is up to .008 below flush.
5. One of the primes set to .0045 below flush did not fire but was pushed further down to .0095 below flush

No doubt from my experience. Never seat primer flush or a couple thou below the head. Seat by feel to the bottom of the pocket. Firing pin energy is lost if it has to push the cup forward. I think the primer manufacturers all say seat to the bottom of the pocket. The only FF I ever had was when trying different seating settings on my tool.

 

[Frankm]

If these are LR cases any chance you got a few LP primers mixed in? They re slightly shorter …. Just a thought b

 

[Steel Mover]

The old way to fire form is to pull the bullets out to engage the lans on bolt closing then fire the case se. You headspace in that rifle is just a hair off, as in too long. So pull the bullets on the FF and reseat to set them out .to make the ogive 005 longer, until you get resistance on the bolt lock up. The object is to get the brass fire formed for that chamber, then neck size only.

 

[Vandelayindustries]

My first thought was you had particularly deep primer pockets. . . and you do.

My CCI 200's are at that thickness too. And with pocket depths of .131 those primers are at .006" below flush before they even begin to touch. Typically, I like a minimum .003-.004 crush, which would make this ~.010" below flush. That's a pretty long reach for a firing pin and if you pin is on the short side, that'll result in FTF's. So, yeah . . . I think you should really check the protrusion of your firing pin. You many need to use different brass for this gun that doesn't have such deep primer pockets.

Protrusion is .061. Think I still need different brass?

 

[DShortt]

Protrusion is .061. Think I still need different brass?

Fully seat the primers. See what happens then.

A primer pocket .005" deeper than spec isn't ideal, but it *should* work OK if everything else is correct.

Now, if your cases are a bit short for your chamber, then we're beginning to stack tolerances.

 

[Vandelayindustries]

Fully seat the primers. See what happens then.

A primer pocket .005" deeper than spec isn't ideal, but it *should* work OK if everything else is correct.

Now, if your cases are a bit short for your chamber, then we're beginning to stack tolerances.

I did fully seat again. They are at .014” below flush. All FTF

 

[Straightshooter1]

Protrusion is .061. Think I still need different brass?

That .061 is just fine and I'd say on spec.

I did fully seat again. They are at .014” below flush. All FTF

I assume you're seating by feel. And .014 is really deep, even for a firing pin at .061. CCI 200's cup height is ~.118", which means with a primer pocket .131" deep, for the cup to touch bottom it'd have to be .013" below flush and you appear to have them right there touching (+ a hair). I wouldn't seat them that deep as that's .008 or .009" of crush on the anvil. I don't seat by feel, so I have more control over how deep I will seat them.

I assume these Peterson brass are virgin??? If so, then like has already been mention, if the case headspace is kind of short, this will add to the problem. . . not allowing the firing pin to make hard solid contact with primers that deep.

Different brass with not so deep pockets would probably resolve the problem. And after virgin brass is fired, that'll also help resolve the problem.

Anyway . . . those are my thoughts on the issue. Good Luck.

 

[Oso]

Potential Issues:
Primers - faulty manufacturing
Case Dimensions - shoulder of cartridges is short of chamber length
Primer Pocket - primer pockets cut too deep
Firing Pin - short pin protrusion
Firing Pin Spring - short or weak spring

Ignition Issue - Bad Primers:
Easy fix. Pull bullet from light strike rounds. Set powder aside to put back into round. Decapping the case. Insert new primer and add back powder and reseat pulled bullet. See if fires.

Ignition Issue - Non-Primer:
None of these sound like are severe enough on their own to be root cause. However, a couple of them together would do it. Short Firing Pin protrusion &/or weak Firing Pin Spring plus short Brass Cases at shoulder… this would be enough.

Process of elimination. Jamming bullet to ensure solid strike, as opposed to simply pushing short case further into chamber. New firing pin spring is cheap, etc.

 

[bpd459]

Why was your ammo acclimated to 10f?

 

[shoot4fun]

Well, someone may have different information to set me straight, but.

My understanding is that the primer needs to be seated to the bottom of the primer pocket with enough additional 'crush' to seat the primer anvil for reliable ignition.

So it would seem that the combination of these primers, the depth of the primer pockets and possibly firing pin protrusion being a bit shallow are stacking up and causing your ignition problems.

Seating a primer shallow and not to the bottom of the pocket is not a viable option as I understand ignition.

If someone has contradictory information from a verified source, I'd seriously like to have a look at that. It would be new information to me, and I'm always open to learning new things.

Edit to add - the reason the primers on the fired cases are flush with the case head is because the chamber pressure drove the primer back against the bolt face during firing.

My point was primer pockets on virgin brass are usually tighter and one must take extra precautions to make sure they are to "crush" for reliable ignition.
No one has asked as far as I can tell but wondering if the OP tried firing the rounds in question again. Many times that first strike will push the primer down enough to make contact with the bottom of the pocket.

 

[ShtrRdy]

Protrusion is .061. Think I still need different brass?

No, you should be fine. You'll get this figured out. It now seems to be pointing to excess lube inside the bolt and the cold temperature.

Is the bolt like a Rem 700? If so you could use the Marine bolt disassembly shoestring trick.

You can use a shoestring while still in the shoe/boot:

 

[DShortt]

My point was primer pockets on virgin brass are usually tighter and one must take extra precautions to make sure they are to "crush" for reliable ignition.
No one has asked as far as I can tell but wondering if the OP tried firing the rounds in question again. Many times that first strike will push the primer down enough to make contact with the bottom of the pocket.

Everyone has varying experiences, no doubt.

I myself have rarely been successful with re-firing a round. Once in a while, but usually not.

 

[Vandelayindustries]

Why was your ammo acclimated to 10f?

That’s what it was outside. It’s a hunting rifle so I need to know what it’ll do from 0*F to 90*F

 

[Vandelayindustries]

My point was primer pockets on virgin brass are usually tighter and one must take extra precautions to make sure they are to "crush" for reliable ignition.
No one has asked as far as I can tell but wondering if the OP tried firing the rounds in question again. Many times that first strike will push the primer down enough to make contact with the bottom of the pocket.

Yes I’ve tried to fire again. Still doesn’t fire

 

[Vandelayindustries]

No, you should be fine. You'll get this figured out. It now seems to be pointing to excess lube inside the bolt and the cold temperature.

Is the bolt like a Rem 700? If so you could use the Marine bolt disassembly shoestring trick.

You can use a shoestring while still in the shoe/boot:

Yes it’s a 700 clone. I did just pull it apart and there is a healthy amount of grease back by the shroud and back of the sprimg(opposite side of firing pin). I’ll clean it out and put it back together. See what happens tomorrow because I’m out of daylight here

 

[neckturner]

healthy amount of grease back by the shroud and back of the sprimg

Grease will thicken at low temperatures.

G96 is proven to be effective as temperatures drop. Food for thought.

Wayback Machine

 

[Vandelayindustries]

Grease will thicken at low temperatures.

G96 is proven to be effective as temperatures drop. Food for thought.

Wayback Machine

Still odd to me the factory rounds fired just fine. Maybe the grease in conjunction with the deeper primer pockets were enough to cause the issue? Guess I’ll know more tomorrow

 

[jelenko]

.014” below flush

I'm not understanding how that can be if the primer pockets are within spec.

 

[Vandelayindustries]

I'm not understanding how that can be if the primer pockets are within spec.

.031 primer pocket depth - .025 primer thickness is .006 below flush just for the touch, no crush. I’m using a RCBS bench primer. I will say these Peterson pockets were abnormally easy to seat. On lapua, starline, Winchester, and alpha brass I usually have to use a fair amount of force to get that slight crush. I go by feel. Usually end up around .004ish below flush on other cases. Maybe that was part of my problem with why these got sent down so far. In the future I’d do almost no force on these at all.

I did measure some other depths on starline, alpha and lapua. The .031” depth really isn’t that far off. Most of those other brands were around .027-.030” so I’m rethinking the depth being the issue. Hopefully cleaning the grease resolves the issue