Primer Diagnosis Help Needed

[25-06 Mike]

Hi all,

Recently I posted having problems with a load for my B78 25-06, Thanks for all your input !!

I have some detailed pics of the blown primers, and would greatly appreciate your thoughts.

This are Fed210 primers, and I am wondering if the Fed215 being magnum primers might be a better stronger choice ?
Could this be a rare case of defective primers ?
I am well aware I am reaching max pressures, however reducing the load affects accuracy greatly.

Rifle Browning B78
Load 54 gr RL22
Nosler 110 AccuBond
Bullet Jump to Lands Aprox 10 mil

Thanks all a Mill !!!

 

[JLT]

By the looks of some of those primers I would say that the load is significantly over maximum for your rifle. When you start seeing muffin tops on the primers, it's time to back off regardless of accuracy considerations. Primer cup thickness won't matter much if pressure backs the primer out of the pocket. Note the point of failure in some of the primers - they blew on the back edge, which was unsupported by the case at the time of failure. I'd venture a guess that any primer would blow under these conditions and I'll bet the pressure is exceeding safe levels by quite a bit. Please don't risk your nice falling block Browning, never mind your flesh and blood!

I'd start a work-up with a different powder. H4831SC has always yielded good results for me in the .25-'06 with bullet weights in this range.

One more thing . . . . over-sizing the brass can result in this condition, too. How far are you bumping the shoulder when you resize?

 

[fguffey]

The first thing I would check is case travel, I am the fan of cutting down on all that case travel. And then there is supported and unsupported; I want my primer pockets to support the primer. If in the event of things my primer backs out before the case returns to the bolt face I suspect my primers are not being supported by the primer pocket. It is not something that happens suddenly, all at once and without a warning, my bolt face will show signs of hot high pressure metal cutting the bolt face.

And then again; I want to cut down on case travel.

Your pictures show primers that have been abused, I do not see the same abuse on the case head and I do not know the diameter of the primer pockets.

F. Guffey

 

[savagedasher]

Was the cases new? From what I see the primers are loose in the pockets . Larry

 

[John Russell]

These primers are not showing pressure - muffin tops come from headspace - the the pin indents do not show pressure.

I would suggest going to another primer to make sure it isn't the primers - primers do not blow out in pinholes on the edge of the primer cup under normal (and high) pressure. I have boxes of Federal primers collecting dust.

And check headspace of your new cases - with the B-78, it is easy. Put layers of scotch tape on the case heads, adding one at a time, until you feel resistance to raising the block.... and count the layers. Each layer is = 0.002"

 

[JLT]

54 gr. of RL-22 is stout charge with a 110. Would not rule out over-max in your rifle.

 

[watercam]

I think it is a combination of excess headspace and hot loads. The Federal primers are soft, I would try another brand for sure. Have your headspace checked by your gunsmith or you can rent gauges from
www.4-dproducts.com for very little money. Block should close on a Go and not close on No-Go.

 

[savagedasher]

I don't see any signs that primers had any tension on them.
Looks like to me the primer pockets are too loose . Larry

 

[John Russell]

I think it is a combination of excess headspace and hot loads. The Federal primers are soft, I would try another brand for sure. Have your headspace checked by your gunsmith or you can rent gauges from
www.4-dproducts.com for very little money. Block should close on a Go and not close on No-Go.

First, it can close on a no-go. The Go gauge is SAAMI minimum, a no-go is 4 thou longer, but SAAMI max is 10 thou longer than the go gauge. No-go is designed for builders, not designed to test for limits.

Second - what the actual measurements are, is somewhat irrelevant - it is how much longer the chamber is, compared to HIS brass is... is what counts.

 

[RonAKA]

I would go to a slower powder like Retumbo and work your loads back up again. I think you have high pressure and high headspace. Make sure to only bump the shoulder of your cases by 0.001" when you resize the case.

 

[powderbrake]

I had the same problem on a 22-250, which I noticed after a prairie dog hunt. The primers blew out at the corner. They were Winchester Large Rifle primers. The blowouts also ruined my bolt face, by fire etching a ring on the face. I sent the primers and cases to Winchester, and they confirmed the primers were bad. They requested I send them all the primers I had from that lot, and all the cases. They replaced my primers, replaced my brass, and offered to have the rifle repaired. Since it was a trued Rem 700 action with a custom barrel, stock and trigger, I asked they just pay for the bolt repair, which they agreed to do. I sent the bolt to GreTan and it was fixed in a week (plus he bushed the firing pin hole and turned down the firing pin). I replaced the ejector with a new one from Brownells, it all worked out fine, and the rifle is better than before.

So, send the primers and cases to Federal for review, and check your bolt face. Here are some pics so you can compare.

ps. I had two lots of primers, and was not able to distinguish the lot numbers, so now I record case, primer, powder and bullet lot numbers on all my reload box labels.

 

[CTK]

How is an etched bolt face repaired? If it is ground down and polished, would that not increase headspace? Doubt would be enough to be a problem, just trying to understand. One of my rifles (Bighorn action) has user replaceable bolt heads. Have some solace in that if damage ever happens, I can just buy another head.

 

[25-06 Mike]

Thanks all,

Some additional info,
Cases are neck sized with about 1 to 2 mil of shoulder bump using a bump gauge insert, so there's hardly any case travel.
Primers are seated with an RCBS bench priming tool.
Cases are cleaned every reload.
Brass is Federal, however I also experienced just one primer blow with Winchester Brass with the same load, and with the same Fed210 primer lot.
I usually press firmly on the priming tool lever when seating primers, but have never experienced anything like this.

Thanks a mill again,

 

[BoydAllen]

You have some fundamental reloading issues. First of all, you need to get the proper tool to measure the shoulder to head dimension of your fired cases so that you can then set your FL die properly. What Someone referred to as muffin top of your fired primers is the direct result of this. With a long case like the one that you are using, there is a lot of area to hold the case in the front of the chamber during firing. If the pressure had been high, the case head would have come back to the bolt face, and you would have hot seen the primer above the head, which you did not show, but which had to be the case given their shape. With the primer edge unsupported, there was enough pressure to cause the blowouts that you had. If the primer had been supported. That probably would not have happened. Another issue that is often overlooked is the accumulation of carbon in the throat of the chamber. Ordinary cleaning may not remove this, and when enough accumulates it can cause pressure issues.Another source can be cases that are close to or over max. length. With the shoulders of your cases bumped back too far, when the case is pushed forward during firing (until it is stopped by the chamber shoulder), even though the overall length of the case is within spec. with the shoulder too far back, there will be too much neck in front of the shoulder and that will crimp into the bullet because of the angle at the front of the neck part of the chamber. Another issue which may be involved is not working up to a load, starting low and bringing charge weights up in small steps. For this particular application I would do my investigation of charge weights in half grain increments. Finally, there is the matter of how one should react when a round shows obvious signs of a problem. STOP SHOOTING! Don't look at the mess and then load another round from the same batch. You seem to have fired several rounds that had the same problem. Why didn't you stop after the first one? There have been instances where people have kept going to the point where they had to stop because their rifle blew up. If there is a next time, you might want to keep that in mind.

 

[Sniper338]

Yep some issues like above^^^^.

Use a different powder that fills the case well but has less pressure.

I agree both brass issues and over charge with that powder

 

[gotcha]

Mike, This may help explain some of your primer questions. .......... Google: Rifle primer chart. Of all the "big four" American primer mfgs. the Federal (lg. rifle) primer has the largest diameter. Cup thickness for lg. primers is universal for American primers................ I don't know the day to day ability of the Mfg.'s to hold these tolerances. So, powder brake may have good advise. .................. You said your brass was Federal yet those pictured are Remington +1 for Boyd & Sniper338

 

[dkhunt14]

How is an etched bolt face repaired? If it is ground down and polished, would that not increase headspace? Doubt would be enough to be a problem, just trying to understand. One of my rifles (Bighorn action) has user replaceable bolt heads. Have some solace in that if damage ever happens, I can just buy another head.

They turn it out on a lathe and silver solder in a new cup. Matt

 

[CharlieNC]

For what it's worth, Quickload indicates a pressure of 50K vs 65K max which suggests the load is not hot. In terms of setting headspace (HS) I am not comfortable using an arbitrary shoulder bump. So you measure several fired brass and they all check a different length, what do you use to decide on a bump? More importantly how do you know they are still short compared to your chamber before you decide to bump them? I partially seat a primer into an empty case, chamber it, and carefully close the bolt to finish seating the primer. Measure using a headspace comparator to determine the "zero headspace" dimension from which I use to set the FL die to get the desired headspace going forward. It's not unusual to have short brass that takes several firings for it to expand (lengthen) until it fits the chamber. In this situation if bumping based on measuring a fired round, you may end up continuing to increase headspace; not good.

 

[243winxb]

Gas leak or Defective primer. Reduce the powder charge/pressure to find out.

 

[Shaggy357]

I am one of those guys who likes to see the issue from the beginning, rather than part way thru. Kinda like the guy who brings the gun, in pieces, to the gunsmith and asks him to see why it wont shoot. It is much easier to start the diagnosis with a whole gun. I would prefer to start by looking at brass with the primers still intact. Do they appear flattened and level with the case head? Do they protrude a little? Where is primer blown in relation to extractor marks or ejector marks? Do you have any cases that have not had primers removed?

If primers just fell out, you have enlarged primer pockets due to your load being WAY over pressure.

Steve