Pierced primers, help with diagnosis

[jmkasza]

I’ve done a little googling on this, but haven’t been able to get a clear direction on what my next steps should be. My 6mm ARC pierced 4 of 20 primers today and now I feel like there is an issue to fix.

Background: Gun is a factory Savage 110 Switchback in 6mm ARC. I installed a Rifle Basix trigger, but its otherwise stock.

I shot the Hornady Match ammo 108gr ELD-M for barrel break-in and to accumulate some brass. I pierced a primer in the first box and another 2 or 3 over the first 100 rounds fired.

I loaded some 103gr ELD-X and had no issues. Re-sized with Hornady dies, loaded with LeverEvolution (getting close, but below max book load) and CCI 450. No issues, but they didn’t group well.

Next I loaded some 95gr Berger VLD-H with Lever and CCI 450’s. Did the seating depth test and found it favored 0.050” jump with groups about ½”. No primer issues.

I wanted to try the 95gr Berger CH, again loaded with Lever and CCI 450’s. Has potential here, but have not revisited yet to get dialed in. No primer issues. I installed the Rifle Basix trigger right before testing these and was still settling in with the vast improvement over the factory trigger.

Today, I shot 20 loads with the 87gr V-Max loaded with Lever and CCI 400’s. Good potential with groups from 0.650 – 0.890” but I pierced 4 of 20 primers. I also shot 6 factory rounds today, for what it’s worth, no pierced primers.

Why I switched to the CCI 400 with these last rounds (87gr V-Max) I can’t remember. I intend to shoot 450’s with this round, so maybe my issue with correct itself when I use 450’s for my next batch… or maybe not. It got me thinking about the 3 or 4 that were pierced in factory rounds. Is there an issue with the bolt or firing pin that needs to be addressed?

To revisit the primer issues, it was 3 or 4 pierced factory primers in the first 100 rounds. None in the next 100 rounds. Then today 4 of 20 in handloads. Rifle has 230 rounds down it as of today. None of my loads are above max or show signs of pressure outside of the pierced primers, if that is related to pressure in this situation.

I guess what I’m looking for here is some guidance on whether to take it in to have it looked over or just load another batch with 450’s to test. I don’t mind doing the testing, but I’d hate to find out the hard way I should have stopped sooner and it seems like the googling is hinting at a firing pin issue.

 

[GLShooter]

The 450's will do much better for you in this department. Same as the Remington 7 1/2 over the 6 1/2s.

Greg

 

[JSH]

I would check firing pin protrusion. I had not any issues in several Savages, then I did some barrel swaps. Buddy and I measured a couple that saw issues as you describe. I will let you do the home work on what is said to be “enough “ protrusion. I ended up checking all of them and we shall say there was plenty. We set all of them to what we decided was proper, zero issues since then and no misfires either from short/light strikes.

 

[Bill Norris]

You could be seeing results of a firing pin issue but it could also be case capacity differences with the brass.

 

[762plinker]

replace the firing pin, ensure correct protrusion on the new one
a single faulty primer can cause a burned tip on the pin and then easier to pierce the next one

 

[Sandstorm]

Id swap the spring first..This has worked for me in the past.
Especially if it has not happened before with this combination.
( Yea 450s will help remedy this ) missed that one

 

[Laurie]

The Forum's 'search' facility is your friend and saviour here. Right now, there is a 'live' topic on this issue, and it's been covered scores of times.

To summarise:

The CCI-400 and Rem 6 1/2 are weak thin-cup (20 thou') primers originally introduced in the early days of SP cartridges, to wit the .22 Hornet, .218 Bee and similar with MAPs of not much over 40,000 psi. If you ever find any, the original Russian SR primer (PMC SR and likely some Wolf / Tula variants - Murom KVB-223) were very weak too.

Winchester's WSR has 0.021" cup-thickness, better but not a lot.

Federal's two versions of the 205 are 0.0225" and much better

The rest, SR Magnums and match models are 0.025" thick and MUCH tougher.

You need the CCI-450 or similar for a modern cartridge running at over 50,000 psi.

Factory rifles can be more prone to causing primer 'blanking' by fat firing pins with a poor fit in the bolt-face, but as your Savage is managing fine on the CC-450, there's your answer.

 

[Rat Rifle]

All good advice here. I agree that Your issue can be solved by avoiding the thin primer cups. Buy googleing ”Savage”, we can be directed to anything there is to know about Savage rifles, their fixes, etc. The ultimate fix is to get Your bolt ”bushed”. For Me, this is an absolute necessary step, eventually, especially for Small Rifle Primers.

 

[gunsandgunsmithing]

Several things can cause or be factors in primer piercing. Some that get less discussion are a weak fp spring, excess headspace and a rough fp tip. All the other things that you hear all the time can still apply as well. Pressure is a small part and usually is not the root cause. It's the result of stretching and weakening of the brass around the pin. When you think about it in that context, other things start to make more sense. Savages are bad about the bolt face being sorta concave for a good sized area around the pin hole. I'm not talking a bevel around the edge but the bolt face isn't flat. Again, stressing the brass in the area where the primer is. I've seen the problem go away just by truing the bolt face. It becomes very apparent how concaved some of them are once you make a light pass across it.
On Remingtons, it's almost always that the hole is too big for the pin and the brass flows around it. A weak spring lets it flow into the hole also, and the pin can bounce back at it. Same or similar to excess headspace. The case face plants the bolt face and pin and the pin can bounce, compounding the stretch and stress already placed on the primer. The root of the problem in this case is that the pin backed out of the hole leaving the primer to flow, then bouncing back at it. Bounce is not the cause, but an added issue that may or may not go ahead and knock the disc out, that was already very weakened due to the pin backing away. Hope that clears up what I'm saying. No, I don't think bounce is the root cause of primer blanking.

 

[jmkasza]

Thanks for the comments so far. I had a hunch it would be a close split between being a primer issue and a firing pin issue. I checked my book and so far I've loaded and fired 70 rounds with 450's so far, no issues with piercing. I will load up a small batch with 450's and say bye bye to the 400's in this rifle.

I would like to measure the firing pin protrusion too and see if it falls within the acceptable range. Not sure if I have the tools needed to do this at the moment, but I'll see what it takes and figure it out.

 

[Rocketvapor]

Don't forget to inspect pin tip with a magnifying glass.
I use a camera and zoom in then look at it on the computer screen.
Was piercing WSR and changed pin and it went away.

 

[Rat Rifle]

Since You reload, I‘m sure You have calipers, the depth function measures the fp protrusion. To adjust, You need to know how to dissemble Your bolt. Basic google skills will lead You to step by step instructions. I am willing to bet Your pin protrusion is .020” more than it needs to be. Almost all are. The Savage “Brain Trust“ agrees that .035” protrusion is optimal. I have found this to be true. As mentioned, the fp pin nose shape should be a “hemisphere”. Nicely rounded.

You got this ! Best of luck, let us know how it goes

 

[jmkasza]

Since You reload, I‘m sure You have calipers, the depth function measures the fp protrusion. To adjust, You need to know how to dissemble Your bolt. Basic google skills will lead You to step by step instructions. I am willing to bet Your pin protrusion is .020” more than it needs to be. Almost all are. The Savage “Brain Trust“ agrees that .035” protrusion is optimal. I have found this to be true. As mentioned, the fp pin nose shape should be a “hemisphere”. Nicely rounded.

You got this ! Best of luck, let us know how it goes

I have calipers! Thank you for the suggestion. Measured .048" which is acceptable from what I've read... I guess we'll see how the 450's go before diving any deeper. Thanks

 

[BoydAllen]

On protrusion, the primer stops the firing pin, not the dry fire stop. so if you have too much it just lowers the energy delivered to the primer by shortening the effective fall.
Over 20 years ago, I had a lot of conversations with Bob Greenleaf, who retired from Savage after being an engineer for 25 years, and he told me that he set his personal Savages for .035 protrusion. The usual standard is .055-.060. Some time ago, I blanked a primer with the result that there was a flame cut groove across the tip of the firing pin, that would cut primer cups enough that they would leak. By the time that I had removed the damage by stoning, my protrusion had decreased from .055 to .050 with absolutely no ill effect. A weak firing pin spring can let the pressure inside of the firing primer back up the pin tip into the bolt face so that the hole in the face acts like a cookie cutter leaving a round hole and a piece of primer inside the bolt, that may interfere with the firing mechanism.

 

[Webster]

replace the firing pin, ensure correct protrusion on the new one
a single faulty primer can cause a burned tip on the pin and then easier to pierce the next one

I think all FP have about more protrusion than necessary. It's normal. Hot loads thin cups???

 

[Laurie]

Savages are bad about the bolt face being sorta concave for a good sized area around the pin hole. I'm not talking a bevel around the edge but the bolt face isn't flat.

Interesting. One of the three Model 12 PTAs I've owned (still have two of them) is noticeably concave. It'll cause fired LR primers in heavy loads to swell upwards around the firing pin hole, never blank though. I've long wondered if this is a one-off, or a common feature.

 

[Hoot]

Interesting. One of the three Model 12 PTAs I've owned (still have two of them) is noticeably concave. It'll cause fired LR primers in heavy loads to swell upwards around the firing pin hole, never blank though. I've long wondered if this is a one-off, or a common feature.

Sure! Now you all are going to make me go down and measure my 4 bolt faces. 2) PTA 2) Model 12's

Hoot

 

[Laurie]

Sure! Now you all are going to make me go down and measure my 4 bolt faces. 2) PTA 2) Model 12's

Hoot

If they're like mine, you can tell from the shape of the fired primer!

 

[Darwin]

I have a 700 with long firing pin. CCI 450 and Fed 205 can take it but Winchester SR can’t. I’ve read Win #41 are tougher than most.

 

[NorCalMikie]

Needs a new firing pin!
Firing pin needs to be replaced!
Need to check firing pin protrusion!
Firing pin tip defective!
Needs the bolt head bushed!
Needs different primers!
Stock is probably the wrong color!
When you get thru throwing $$$$ at it, try checking the case fit in the chamber.
Factory ammo (makes no difference who loaded it) is NOT fire formed to your or anybody else's chamber.

My guess? Factory ammo too short for the chamber, (till the cases are fire formed) firing pin hits the primer, round goes BANG, case too short for the chamber, primer tries to back out of the pocket and gets "pierced, blanked or whatever you want to call it by the firing pin and EVERYBODY tells you to throw YOUR $$$$ at it trying to solve a problem that can be easily fixed with reloads that havn't had the shoulders pushed back too far to cause the same problem. Start there then get back to us.

And I'll add, out of my 5+ Savage rifles (I've lost count) the only issue with pierced/blanked primers was from the cases being too short, getting the "pierced thang" because the cases were to short.