Primer cratering and blanking.

Greetings. I have a 12FV in 223Rem that I bought during one of the Cabela's sales/Savage rebates last year. I shot the rifle a bit and it is a capable .5 moa rig. It shot so well that I ditched the tupperware and put it in an H-S Precision PST114 stock. I am having trouble with primer cratering and blanking. I hand load nearly everything, but had cratering with factory loads as well. The loads I started with were "known" loads in several other 223 rifles and not max loads. I work in a machine shop and have access to gauge pins and measuring equipment. I removed the firing pin and measured the pin hole at 0.073" while the firing pin itself measured at 0.069". The pin tip appears to have a nice, round radius. The protrusion measured at 0.053" in the fired position. Do I need to look into getting it bushed or are these measurements within tolerance? The other factor is my chamber and throat seem to be on the tight/short side. I can't load anything beyond SAAMI max without the bullet jamming in the lands. This may be causing a high initial pressure spike and blowing the primers. Please let me know if you have encountered similar situations and what you did to correct them. Thanks for your time!! -Quigley

ALL my loads are set "into" the lands by about .010. Build your load that way from the start and you will have no issues.
A load with a .010 jump to the lands may show pressure signs.
That same load at .010 jam into the lands will not show pressure signs and you can go even higher with no ill effect.

As far as primer issues. first thought is brass problems. Brass too short for the chamber, (headspace) round goes off, primer starts to back out of the pocket, pressure pushes the case back against the bolt head and the primer gets punched or cratered.
Once that round has been fired,(the headspace on that piece of brass will be correct) and it has been formed to that chamber. When you resize/reload, make sure you don't push the shoulder back too far or you'll end up with the same issue.
Another way to deal with that issue would be to make the OAL longer so the bullet holds the case back against the bolt head. Again, when fired, that brass will be formed to that chamber.
Single feed and fire the long OAL rounds till your brass fits that chamber.

I had a couple of threads going some time back with the exact issue you are having. Same issue, same model and caliber. Loads toward the lower end were even giving me issues. It was particularly bad with 69 grainers near the lands. After backing off, the problem abated. I think the 12FV has a tight and maybe a short throat. It may eventually open some, and allow for more leeway when reloading.

Your firing pin is right on the money at .069, your bolt head is near max. You could order a new bolt head from Savage and take a chance on getting a better fit. Or order one of the aftermarket bolt heads. Probably the least expensive and quickest option. I bought new firing pins from Savage to cure the blanking issue I had in my 12FV and cherry picked the closest fit. Now have a .0698 firing pin and .072 bolt head hole that hasn't blanked since.

I had the same issue with my TH 11 in 260 rem.

Severe cratering on everything
I ended up getting a PTG bolt head and that made a huge difference.

Original bolt was dished as well.

It’s a fairly common problem with savage and Remington these days.

Can someone tell me what Primer blanking is? Never heard of it.

There are a number of causes of the primer cratering, gets a bit strange.

That said, if your COAL is too long, then you not only need to shorter it up, you need to start from the bottom for developing loads.

The chamber length is recommended, mfgs can change it for their own reason or quality co0ntgrol goes off.

Remington in the Varmint series has been make the throat a lot longer for the ELD bullets.

Relaoding books are a guide you need to determine the COAL and then come up with how you want to deal with it.

I disagree with Nor Cal Mikie approach unless you understand what you are doing.

Abiralry jamming it into the lands and saying there will be no pressure spike is wrong, you may be able to do that with a low load and work up, you may not.

A .010 jump is not going to cause a pressure spike any more than anything else, it may be an issue if you load to max and don't work your way up.

Its not a spike, its a gun chamber thing that some hit the limit before others.

Ergo, that's why you star low and work up.

I will guaranteed you go with a max load and jam it into the lands and you will have extraction issue and likely blown primers.

It could also be the internal case capacity of the brass. I have measured the internal capacity of several different brands and have found a wide variance in different brands.
Using the same powder charge in a case with a smaller internal capacity will show pressure signs while one with a larger internal capacity will not.

Thanks for the responses. I did some more measuring at work. Headspace is good. The throat and leade were extremely short and tight. One of our machinists dyed the chamber then used a finishing reamer to go in and touch up by hand. We use minimum spec reamers and it only cut in the throat and leade areas. I loaded some dummy rounds at varying col and they all functioned fine with no rifling engagement out to 2.350" using 53gr VMAX. This was impossible before recutting. I will post back after shooting again hopefully this weekend.

i had primer problems in my 223 12FV and switched to WSR primers. same loads, same bullets, same brass, problem disappeared. you may be using to soft a primer.

Get the CCI #41 primers. They're have one of the hardest cups in the industry. CCI-450 would be my 2nd choice.

But more prudent would be to re-start load workup with a chronograph and try to correlate velocity and pressure. Sometimes a middle of the road load can exceed Max pressure and generate higher velocity than a Max load in a manual.

I've had a few Savages that had a tight leade in the chamber along with not so long freebore and showed pressure signs with factory ammo when they were new. After a few hundred rounds the leade loosened and pressure signs took a hike.

It sounds like your spec reamer has done its job..

Quote:

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Originally Posted by davinman

i had primer problems in my 223 12FV and switched to WSR primers. same loads, same bullets, same brass, problem disappeared. you may be using to soft a primer.

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Same here, except i went from cci small rifle to cci br-4 bench rest primers. somewhere in the ether there exists a chart of cup dimensions and thicknesses for 'all' the primers. search accurateshooter.com tight-primer-pockets . 3790507 is thread number i believe.

i previously had the same issue on a cva scout rifle, so when it popped up on the 12fv i switched without further investigation.

I wasn't able to get out and shoot this weekend. I'll try to perhaps get it shot at the indoor range some time this week as the weather has turned to crap. Actual possibility of snow tonight. My brass was not an issue that I can tell. I checked it with the l-n-l case gauge and the case expansion seems to be within tolerance as was the headspace. I'm eager to see if opening up the throat has reduced or eliminated the primer issues. I'll post back after shooting...

I was able to bring the rifle with me to work and shoot it on our 100 yard indoor range. Our range uses an Oehler System 85 to do the measuring. It performed VERY well. The primer cratering is still present in certain loads, but the blanking is all but nonexistent. The only loads that had any blanking were the ones loaded with S&B small rifle primers. I have always thought they felt softer than other primers. I even fired a couple max loads using Federal GM205M primers with no blanking occurring. The rifle shoots amazingly well with some loads and just average(but still under 1") with others. I'm sure the H-S Precision stock helps, but the groups that these rifles will shoot are why Savage rifles are the best bang for your buck available. I purchased this rifle during the Cabela's sale for $319 and then got the $100 rebate through Savage. I'll try to post some pictures...

https://www.flickr.com/photos/152940.../shares/3roa9z

Looks like this may have worked for pictures... not sure how to add notes to them. Is it possible to post individual pictures so you can add commentary to each one?